Enslavers II takes place after the end of the Protoss campaign in Brood War. You take the role of a Protoss executor and once again fight Alan Schezar, as well as a Dark Templar fanatic named Ulrezaj and the Zerg broods that these two characters unleash.
Enslavers II (Dark Vengeance), is a set of custom maps that must be downloaded from the internet; you can find them at battle.net. After downloading and unzipping the maps, move the files to the same directory as where Enslavers I is installed (wherever you have StarCraft installed, those should be in StarCraft\Maps\campaign). Once they are installed, click the "Play custom" button after loading your profile. From the screen that opens, navigate up one level in the directory (by clicking the "Up One Level" folder) and open the folder labeled "campaign"; the Enslavers II missions are there. Before opening one, make sure you are opening it with the "Use Map Settings" option, not "Melee" or "Free-for-all".
Mission 1: The Rescue
Just like in the beginning of the last campaign, you start out with some troops but no base. You'll have to take out a small Zerg base in order to set up your own (don't worry, this is nowhere near as tough this time as it was in the last The Rescue mission). Right at the beginning of the mission you'll be attacked by a small group of Zerglings, which your Archons and zealots will take out without you even needing to lift a finger. The base you need to destroy is on high ground to the northwest (watch out, there are burrowed Hydralisks just below the ramps; send your Observer first). The base is a large scattering of Sunken Colonies and burrowed units, for the most part. If you like, you can proceed carefully, using your Observer and your High Templars' psionic storm ability to take out the enemies and minimize your casualties; you have a large enough force, however, that you can pretty much just charge in blindly and take out the whole base without losing more than a couple units.
Get a base started quickly; you have a lot of starting minerals so you can really go crazy on the pylons. To the west, down a ramp and across two bridges, is a wholly undefended mineral field and geyser, so if you're feeling bold you can start a base there at the same time as you're building here (just make sure to send defense as well – since there won't be air harassment for a while, your Zealots should be plenty). With two bases harvesting resources, you should be able to build up ample defenses quickly. Your main base will need Photon Cannons along the northern cliff and guarding the ramp there (if you put them right on the edge of a cliff, they can often shoot down on enemy units in the Zerg base at the bottom of the cliff), and some in the southern portion of your base. Your secondary base will probably be attacked much less often, and you should be able to get by with only a couple cannons defending the bridge.
The two Zerg camps you need to destroy are large and defended by tons of units, so you'll need to build a big army to take them out. To speed up resource gathering, you should take over a third resource patch that is across the bridge from your secondary base and to the east. It is poorly defended (two each of Sunken and Spore Colonies, and some burrowed Hydralisks and Zerglings), so you can take it with just 10 or so Dragoons (or whatever else you've been building). Set up a base there with ample defenses, and then begin buying upgrades and amassing an army (Archons, Carriers, Reavers, and Dragoons is a good choice). By this point the Zerg will be starting to attack you with more substantial forces, but as long as you've built a ton of Photon Cannons around your bases (particularly in the northern portion of your main base) you should be able to weather whatever they throw at you. They'll make at least one big attack with Ultralisks and air support, which will be easier to hold off if you can surround the Ultralisks with Zealots. The brown camp has Guardians and Devourers, but they won't attack your bases – they only attack you much later in the mission, so if you're quick you may never need to worry about them.
You can attack the bases in either order. The brown camp in the east seems to have more heavy units – it's teeming with Ultralisks, Guardians, and Devourers. The orange camp in the West has Lurkers, Scourges, and massive swarms of Hydralisks. It makes no real difference what order you do them in. You can take the brown camp early in the mission with just 12 Dragoons and 12 Reavers (you'll lose most of that army, but not before taking out nearly the entire base); but trying to do the same with Dragoons and Archons may get you wiped out. Or you can build your Stargates in the northern half of your main base (above the minerals), so the edge of the orange base is already softened up (when your Carriers get churned out they get into skirmishes near the cliffs), making it pretty easy taking. However you do it, once you destroy all the buildings in both bases you will be treated to a scene and then the mission will end.
Mission 2: Hung Jury
This mission is a significant jump in difficulty from the last one, and in fact is about as hard as the final mission in Enslavers I. You will begin with a huge base that falls immediately under an attack that you can't hope to repel. The only part of your base that will survive the attack is the island in the far southeast corner, so quickly pull all your troops back to that area and build several Photon Cannons to defend the bridge leading into it; if you build some along the northern coast as well, they can shoot units that are coming around to the bridge (thus getting in several extra shots). While the Terran attack force is large, it consists mostly of small units (Marines and Firebats), so it will take a long time to destroy the abandoned buildings, giving you plenty of time to build defenses.
Once you've repelled the attackers, you'll need to secure a second base. The Terrans leave you pretty much alone for the early part of the mission, but soon they'll start hitting very hard, and with only one source of resources you won't be able to hold it off. The resources you need are directly north of your base, although you need to squirm through some zig-zaggy valleys to get there. There's only a small white base there, but it seems to put up a surprisingly tough resistance – white has a larger base just next to it, so reinforcements will come. You'll need a decent group of Dragoons and Reavers, plus your Zealots, to take it. Once you do, a brown Siege Tank on the cliff to the north may harass you, so the earlier you can get some air units to take care of it (or shuttle some Zealots up the cliff), the better. Hunker down in this base and go absolutely wild with defenses; once you build this base, the enemy almost completely forgets about your main base, and concentrates most of their attacks here. Expect to be losing and rebuilding Photon Cannons pretty frequently for the next little while. In this mission you just need to accept being insecure – attacking a new base before your original base has sufficient defenses, and before your attack force is large enough to take the new base without significant losses – and rebuilding quickly.
In the early part of this mission, Corsairs are quite useful for dealing with Siege Tanks. Unlike other missions you've done in this campaign, this time the Terrans have Siege Mode researched from the very beginning of the game, so deployed Siege Tanks will be a major threat for the entire mission. With Corsairs, however, you can zip to whatever base is under attack, drop some Disruption Webs on the deployed tanks, and they will often just sit there while your Dragoons and Reavers pummel them (or, if they do try to leave the web, they will come within range of your Photon Cannons). Corsairs are also useful against the Battlecruisers that the Terrans will send often; a lone Corsair is pretty weak, but a group of 10–12 can take down a Battlecruiser surprisingly quickly. Since Corsairs are so cheap (same price as Wraiths) and build so quickly, they're perfect for the hectic early portion of this mission. You never got a chance to use Corsairs against Terrans in the Brood War campaigns, but in this mission they really get their chance to shine.
Since you can't hold out against this kind of pummeling forever, you will need to destroy some of the enemy bases. There are two main forces: the white Terrans are located along the northern portion of the map (the base you just established is on what was originally their territory), and the more numerous red Terrans dominate the western half of the map – they have two resource-gathering bases, one in each corner, and another large base in between them in the west-central area. Since the white base is the closest (just a hop, skip, and jump northwest of your new base), it makes sense to take them out first. You can proceed through the canyon to the front of their base and then, once you've broken through, double back to the northeast corner to take out more of the base (including some buildings up on the cliff). And watch out for a Battlecruiser hiding above the cliff on the western end of this base; if you accidentally let some of your units stray over there without the main force coming, you will lose them. While you're destroying this base, don't empty your old bases; red is likely to hit the southern portion of your second base while your forces are busy in the white base, so you should keep some troops at home for defense. Just like with the last base you fought, there will be a very hectic period where your units are spread too thin to defend any of your bases sufficiently, and you're just going to have to accept some ugliness for a few minutes. Once you've thrown down a Nexus and some Photon Cannons, things will quiet down a little, although red will never stop making forays at this base. Also note that white still has buildings further to the east, but don't worry about them just yet; those buildings are dangerously close to the red base, and now that you've destroyed white's Command Center and gatherers they're no longer a threat anyway. Establish a new base here, and build up substantial defenses – again, the enemy is going to attack this new location a lot.
Although white will be a non-issue by now, red will step up their attacks. They'll send large groups of Battlecruisers and Siege Tanks with the usual ground and air support, so you'll need large and mobile forces (not just Photon Cannons) to hold them off. Unfortunately, you don't have access to Dark Archons in this mission (or indeed anywhere in this campaign), so you can't use the cheap tricks you used in the finale of Enslavers I; you're just going to need to weather bigger and bigger attacks the old-fashioned way. Keep your Corsairs at whatever base is getting hit the most, and use them to deal with Siege Tanks. Carriers are particularly useful later in this mission, both for defense and offense. Minerals are scarce, though, so if you've built a lot of other units then you may only get four or five Carriers churned out before you run out of minerals at your three existing bases. The last thing to remember in your defense is that red has nuclear silos, so make sure to keep an Observer handy. (Red usually only ever tries to hit your new, northernmost base, but if you are nervous and have enough psi you could put an Observer at each base.)
Assuming you're surviving the pummeling, once you've built up a large enough attack force you can try to approach the red base in the northeast corner (the closest to your newest base). When doing this, it is necessary to send your Carriers ahead of the main force; your ground units have to walk through narrow canyons, and the cliffs above are littered with Siege Tanks that will harass you if you try to walk past. So send your Carriers ahead to take out the tanks (most of the tanks are also defended by a Missile Turret or two, but if you have a large group of Carriers these will not be a problem). Don't leave your ground army too far behind, though, because sometimes you might bump into one of Red's large attack forces on the way to your base, and you don't want your Carriers to face them alone. So keep your ground forces just a little bit behind the Carriers. Also be sure to bring Observers, because there are bound to be Wraiths flying around here, and the moment you engage them they'll cloak.
The red base in the northeast will put up a nasty fight. There's no particular trick to taking them out, just old-fashioned fighting. Reavers and Archons are useful here. Prioritize Siege Tanks and Science Vessels and take them out (or Disruption Web the Siege Tanks); if a Science Vessel gets an EMP out, you could see 12 Archons turn into nothing very quickly. Once you've taken this base out, you may want to send in some Probes and build a Nexus to gather its rather ample resources. Don't waste too much extra money actually building defenses here, because once you've won this battle red will be back on its heels, and the mission is almost over anyway. Your surviving attack force should be enough to defend the base for the short time it takes to recuperate and replenish your ranks. Once you're ready, proceed south to take out the rest of the large red base (again, remember to clear the path with Carriers first, unless you want a nasty surprise). Clearing them out will take some time, but it should be easier than the last two bases you fought; the defensive troops will be scattered and disorganized, and it should be obvious that red is on its last breath. Once you've finished off red, if the mission hasn't ended yet, fly around and make sure you haven't missed any brown Missile Turrets anywhere on the map; there are also some white Supply Depots and a Starport on high ground in the north central portion of the map (west of your third base) that you might have missed on the way to red. Once you've destroyed all the Terran buildings on the map, victory is yours.
Mission 3: Nemesis
This mission will be a doozy. You're given the option of retrieving the Khaydarin Crystal in the northwest corner of the map, or destroying Schezar's Command Centers in the northeast. To follow the canonical storyline, you have to choose the crystal.
You start in the center of the map with few defenses. Your first focus should be on increasing your defenses (early on, you'll probably need at least five Photon Cannons at the north and south entrances, and ground forces) and building up an army as quickly as possible to secure more resource areas – with only one base, you will not be able to harvest fast enough to prevent being overrun. Build mostly Dragoons and Reavers in this early part of the mission – there are not many air forces on the map yet, so you can focus on ground control. The orange base where the crystal is, and it is very heavily defended, so the way to win this mission is to slowly take over the map and build up a large force.
There are several white Terran/Zerg bases which pose the most immediate threat to your survival, and which are also the ones you will need to take to secure resources. There are small white bases at both southern corners of the map, and larger bases in between them (one directly north of you, one directly south). The corner bases are not well-defended and should be your first targets for expansion. The one in the southeast has nothing but a couple Sunken Colonies and can be taken with just a couple Reavers and Dragoons; once you have set up a base there, you can build up an army to take the one in the southwest corner, which will put up a bit more of a fight.
While you are taking these bases, you will also need to constantly rebuild the defenses at your main base in particular, and perhaps the satellite bases as well. Your main base will be under constant attack from all sides: Terran ground forces will frequently assault your photon cannons at the north and south entrances, and Siege Tanks will shoot at you from the cliffs above. Zerg will also drop units to the west of your base and try to come in behind your minerals, so you will need cannons or units back against the Western cliff as well; before long, you will also start facing heavy air attacks from Wraiths and Mutalisks (later in the game they will be replaced by Battlecruisers and Guardians). The sooner you can build up an air fleet, the better you will be able to defend against these threats. At this point in the game, you'll be facing the most attacks at your main base, and you'll be getting hit less in the southeast (but still hit hard enough that you'll have to rebuild your Cannons there regularly), and hit very infrequently in the southwest – but that doesn't mean you can leave the southwest alone, as there will still be some attacks there.
Now you can work on slowly building up an attack force to take the crystal. The orange base defending the crystal is on an island, so you will need a large air fleet to have any hope of penetrating it; use carriers for this. (You should have at least two Stargates and try to keep churning out Carriers constantly, as enemy attacks will inevitably destroy some of your Carriers while you're still building the fleet). If you have lots of extra vespene gas and few minerals (from building bases and Photon Cannons), now is a perfect time to build as many Archons as possible. Finally, keeping the final assault in mind, you should build three or four Arbiters with the Recall ability and energy upgrade researched – that will be much more effective than Shuttles when you need to get your ground units across to the island.
By now you may be running low on resources, and the constant attacks may be keeping you from building an offensive force. So taking out the larger white bases north and south of your original base should help; the northern one in particular is resource-laden and less well-defended than the southern one. Once you have taken them, you can set up more bases and churn out as many units as possible (you should be hitting the psi limit by now; free up some psi by taking the probes from your bases that are out of minerals and send them into enemy camps). Be forewarned, though, that with white mostly out of the way and the center of the board yours, orange (Zerg) and red (Schezar) will start attacking like crazy; at this point in the game a large fleet of Guardians and Devourers may wipe out your southern and middle bases (forcing you to re-climb the tech tree in your new bases) and fleets of Battlecruisers, Siege Tanks, and Goliaths may begin to pummel the eastern side of your northern base. Your other bases should be left alone in this part of the game and all attacks focused on the north, so gather your troops there. If any of your satellite bases, especially ones with no tech tree buildings and few or no resources left, get hit with a major attack, feel free to let them fall – you don't need those bases anymore, and trying to protect them is just a resource drain. You will save resources by consolidating to one or two bases and not spreading your units so thin.
Assuming you survive the pummeling, make sure you have 10–12 Carriers, as many Archons and Reavers as possible, and at least three Arbiters. Then send the Carriers directly west from your northern base, moving along the very top of the map until you see the orange Spore Colonies. Do not try to penetrate orange anywhere else – most of their base is ringed by another white base and you would have to fight through twice as many defenses if you came from another direction; if you attack the hole in the northwest part of their base, you should just barely be able to puncture their defenses. Once your Carriers have taken out the Spore Colonies and cleared out some space on the ground, send in your Arbiters and then recall in as many Archons and Reavers as possible. The Archons, Reavers, and Carriers can do their thing, taking out as many units and defensive structures as they can (don't worry about destroying the harvesters and Hatcheries) while the Arbiters pull back out of harm's way. Your attack force will probably be overrun, so don't expect them to be able to take out the whole base; just clear as much of a path as possible to the crystal. Once the path is more or less clear, tell your Probes to stop harvesting and gather them in a bunch, then send your Arbiters to the crystal – hopefully you still have some Carriers or Archons alive to distract the enemy and draw their fire. Once your Arbiters are over the crystal, Recall in as many Probes as possible. Ignore the Sunken Colonies there; as long as at least one Probe survives them and touches the crystal, you will win the mission.
Considering the difficulty of the level, provided by the sheer amount AND size of the enemy bases and the forces they produce, one may ask if there is a way to "cheese" through the fight. Well, there is one and it's doable in less than 10 minutes. It should be mentioned that it leads to missions 4A "Desperate Measures" and 5A "Showdown", which is the canon version, but if you want to play the other branch, this strategy can't be applied.
Once you start, quickly train a bunch of Probes and put them mostly on minerals - you will need almost no gas for the whole mission. The strategy is to produce mass Shuttles, so build two Robotics Facilities ASAP and start pumping. In the meantime research the Shuttle speed upgrade and, optionally, the Plasma Shields upgrade. It's possible to win with 5-6 Shuttles, but it's better to have 10-12 just to make certain. Load a single Probe inside each one and head towards the Crystal in the Northwest. You may also use Mojo to draw some fire for the Shuttles. Unload the Probes on top of the Crystal - once one of them reaches it, you win.
Mission 4A: Desperate Measures
This is an interesting and fun mission. You have one hour to take your Dark Archon to five Kaydarin crystals, mind-controlling Zerg along the way to reinforce the troops you start with. The time limit should not be a major problem, as the mission can be completed in 40–50 minutes without much trouble; it just means you can't dally along waiting for your shields and energy to regenerate all the time.
You don't start with much, but it's just enough to get you through the mission. The first crystal to go for is north of your position, on higher ground. You will need to proceed slowly, taking out Sunken Colonies and units one at a time to get up the ramp and to the crystal. Use your Scouts to take out isolated Sunken Colonies (such as the one up the cliff just north of your starting position); for Sunken Colonies backed up by Spore Colonies or Hydralisks, use your High Templar to create some hallucinations of your Dragoons, then attack the colony with Dragoons behind the hallucinations. Slowly proceed west this way, then north when the path forks, and you will reach the ramp to higher ground (by now you should have gone past two or three Sunken Colonies). At the top of the ramp is one Sunken Colony, two Spore Colonies, and several Hydralisks; if you lure the Hydralisks out you can kill them with a psionic storm from your High Templar, and there should be just enough room for the Scouts to take out the Sunken Colony without getting hit by the Spore Colonies. Once that is clear, you can go up the ramp and proceed west towards the crystal. By this point you are in the middle of a Zerg base, so move carefully; psionic storm may help to deal with a small group of Zerglings and Hydralisks. There is one more Sunken Colony to deal with, which you can probably take care of just with your two Dragoons (just make sure to pull one back when its shields get low). After that, send your Dark Archon to the crystal; the moment you touch it, the whole base will become inactive and enemies will stop attacking you, although they will still be sitting around if you want to mind control any (a Queen may come in handy for the next crystal, which is defended by several Ultralisks). You can probably be done with this crystal in 5–7 minutes.
Now move north towards the base that has the next crystal. Be careful about the yellow Spore Colonies on the cliffs to the east; if you want you can take them out from below with Dragoons. You will go down a ramp and through a narrow strip of land leading north; here there is a burrowed Lurker (send your Observer ahead of your other units), which you absolutely should mind control; Lurkers are the key to winning this mission. After you have it, proceed northeast along the bottom of the cliff (again, you can take out the Spore Colonies above you with your Dragoons and Lurker, then they won't bother your Scouts) until you reach a ramp going up to higher ground. At the top of this ramp is another Lurker, which you should mind control, and some other units that you can kill easily; just above them are a single Sunken Colony and an Ultralisk; there are some Spore Colonies and Overlords around here, so you can't use your Lurkers or Dark Templar just yet. Maneuver carefully around the Sunken Colony, keeping out of its range, to take out some of the Spore Colonies surrounding it, and kill some of the Overlords if you can; once you have the detectors out of the way, you can take out the Sunken Colony with your Lurkers. As for the Ultralisk, you can mind control it if you have enough energy, or kill it with your Queen's Spawn Broodlings ability, or just kill it old-school; either way is fine. (There are more Ultralisks in this base later, so there's no need to wait around for energy to mind control this one in particular; and besides, Ultralisks aren't that useful in this mission, although they certainly don't hurt.) Keep going through the base this same way – taking out detectors while avoiding Sunken Colonies, then sending your Lurkers in to finish the job. Just watch out for a group of Hydralisks and an Ultralisks north of where you met the first Ultralisk. Once you're through them, go north through a narrow strip of higher ground, and you will be just below the crystal. This crystal is guarded by two Ultralisks and several Hydralisks. Mind control the Ultralisk or hit it with Spawn Broodlings; during the confusion caused by this, you should be able to send your Dark Archon in unharmed. Once he touches the crystal, the enemies will become inactive. By now, 10–15 minutes have probably elapsed.
Now head all the way back south from where you came; near the lower center of the map there is a ramp leading down to the next area. Gather your troops that don't have air attacks at the bottom of the ramp, and move forward with your Scouts and Dragoons. Soon you'll encounter a large number of Mutalisks hovering around; fortunately, they are quite spread out, so you can pick them off one by one and lead them away from the main group to kill them. As long as you don't pull out more than three at a time, your two Scouts and two Dragoons will be able to take care of them handily. Don't bother trying to psi-storm them; they are so spread out you'll only hit one or two, and psi-storm will soon be useful somewhere else anyway. Continue cutting a path through the Mutalisks towards the south; when you reach the bottom of the map, proceed west (killing Mutalisks on the way) until you see Spore Colonies. From there, bring in your Lurkers to take them out, and use them or psionic storm to take out two groups of burrowed Hydralisks just behind them. With them out of the way, you can send your Dark Archon in unhindered. Don't bother mind controlling anything down here, as these small units are not worth the energy; just touch the crystal. You should be 20–25 minutes into the mission now.
The last two crystals are not on the same landmass as this, and there is no bridge. Fortunately, directly north of the crystal you just destroyed there are two Protoss Shuttles. Mind control them and shuttle your units north (there is a single Spore Colony in the way, so you may want to destroy it from below with your Dragoons and Lurkers) and drop them on the low ground. Try to do this quickly and be wary of this position, because there are some large marauding groups of purple Zerglings and Hydralisks that may come across you at random; if they do, a psionic storm should take care of them.
The next base to take out is the purple one north of you. (Judging by what's in it, it seems the mission was designed such that you're "supposed" to do that base last, for plot reasons, but you'll find it easier than the white base, and it has some units that will come in handy at the white base.) You will need to shuttle units to higher ground again; use your Dragoons and Lurkers to destroy the Spore Colonies on the cliff and then shuttle your units up there. There are a bunch of Sunken Colonies here, all of which you can destroy the same way you did in earlier bases (take out the Spore Colonies and Overlords, then use your Lurkers on the Sunken Colonies). Ultimately you want to head northeast, around a curling stretch of cliff, and down the ramp into their base. This spot has a lot of things that can kill you, including the usual Spore and Sunken Colonies, Devourers, and Dark Templar (bring your Observer!). Proceed slowly, taking things out one at a time from far away. Make a special effort to destroy the Spore Colonies and Hydralisks around the Devourers and then mind control the Devourers; they will come in handy at the final base. (You want to isolate them before mind controlling them, though, so they don't get immediately killed.) For the Dark Templar (two hanging around the first Sunken Colony, and two hanging around a Spore Colony just below the crystal), a single psionic storm will put their health down in the red and then you can finish them off with Dragoons or Lurkers. This base is slow going and will take more time than the last ones, but the overall strategy does not differ much from that of the second base you went through. Once you touch the crystal the enemies go inactive, and hopefully you will have stolen two or three Devourers. You should be 30–40 minutes into the mission by now.
The final base, white, is in the center of the map and guarded by a massive fleet of Guardians and Scourges, as well as a bunch of Sunken Colonies. It's up on high ground, and the ramp leading to it is choked by Sunken Colonies; between them and the Guardians, a ground attack is inadvisable. The Scourges are less of a problem; you can take them out with your Scouts and Devourers. You won't survive – eventually the Scourges will destroy all your air units – but the main thing is just getting rid of them. Your High Templar might also be able to take out a group or two of Scourges with a psionic storm if you put him just below the cliff; be very careful around here, though, because not only can the Sunken Colonies above hit him, but also there are a large hordes of Hydralisks and Zerglings burrowed all around the area. You don't need to destroy all the Scourges above the plateau; you only need to destroy about half of them, enough to open up a clear air path to the crystal. Once that is done (and your Scouts and Devourers probably dead), simply load your Dark Archon into a shuttle, which the Guardians and Sunken Colonies cannot touch, and drop him directly on the Crystal. The mission ends; if you did things right, all this should only take 40–50 minutes.
Mission 5A: Showdown
You are in for one long, hellish mission now. Finally you have a chance to kill Alan Schezar, but first you will need to deal with an EMP generator, in the middle of a strong Protoss base, that removes your units' shields every 10 minutes. The EMP generator is not as huge of a pain as it may sound (10 minutes is a long time in StarCraft), but it can still cause you to get destroyed quite suddenly if you don't pay attention to it. As long as it's up, you'll want to keep your eye on the clock, and when it's close to EMP shock time you'll need to make sure your defenses are ready, and certainly make sure you're not going on attack when a shock happens (not only will your attack force be ripped to shreds, but your bases will become easy prey as well). The enemies enjoy gathering troops just outside your base and waiting for an EMP shock to attack while you're weak, so if you see them doing that you may want to send a foray a minute or so before the shock to take the attackers out, or lure them to attack early. Because of the EMP, don't waste resources investing in shield upgrades too early in the mission (later on, when you have a couple thousand resources sitting around not being used, then you can do those upgrades), and don't rely too heavily on Archons until the EMP generator is taken care of.
You begin the mission in the corner of an enormous map, with a relatively well-developed base. You don't have many resources, though, and you will certainly need a ton for this mission (over the course of the mission, don't be surprised if you have to build up 12 Carriers/Reavers/Archons/whatever more than once, as you will be suffering quite heavy losses). Therefore, you will need to quickly focus on expanding, and building powerful troops that will be able to defend your expansions while you're getting set up. There are three expansions that are accessible to you early in the mission and are poorly defended, shown with numbers on the map below (other important locations are also marked, for later reference):
------------------------------------ | EMP | | Nexus-P | | | |Nexus-W | | Nexus-W Schezar| | 1 2 | | | | | | Start 3 | ------------------------------------
Expansion 1 is defended by a Pylon with a couple Photon Cannons around it, and can be taken with a single Reaver (although you should send others along to back it up in case it gets attacked). This expansion has no gas, but a ton of minerals – enough to get you through the EMP portion of the mission pretty comfortably. Expansion 2 is totally undefended, and has both minerals and gas. It's in an awkward place, though, hard to defend with ground units and easy to attack from several directions, so holding onto it will be difficult. (You will need to hold onto it anyway, though.) Expect heavy attacks here from both the Terrans and the Protoss; if you lose a base entirely, it's likely to be this one. Expansion 3 is defended by a Missile Turret and a few weak units, so it also is easy taking. Don't worry about it until you have a nice force of Carriers, since by then it could be taken without batting an eye, whereas you try to take it with ground units at the beginning of the mission it requires at least a bit of work.
You will need to set up bases at all three of these expansions and defend them well. Don't neglect your main base, either; you'd think it would be cushioned by these other bases, but the enemy will still often sneak through and hit your main base hard. Also, don't rely on Photon Cannons alone; both enemies love Siege Tanks and Reavers, and Photon Cannons can disappear in the blink of an eye if you get attacked by them and have nothing to counter it. For this mission, once again Corsairs are invaluable. Since you have so many bases, it's not possible to keep a full army stationed at each one, and Corsairs are fast enough that they can zip from one base to another quickly; just put Observers in front of each base to get a bit of a prior warning whenever an attack is coming.
You will spend a good long time just defending yourself, struggling to stay alive while building up an attack force. The EMP device has a number of Dark Templar and Reavers defending it, and the path to get there weaves around several other Protoss bases, so don't attack it with ground units (it will look something like a large number of flies splatting against a windshield). Therefore, you should probably build Carriers and Corsairs for the attack; you should be able to take the EMP device with about eight Carriers and ten Corsairs. (That doesn't sound like much, but considering how hard defense is in this mission, it will take a long time to build up a force that large and enough defenses to leave behind.) Once you have that, proceed directly north from Expansion 1. (Again, remember not to attack when an EMP blast is imminent.) There is a white Protoss base on higher ground here; the base is large, but its defenses are measly, it has only two or three Photon Cannons. Drop a Disruption Web on the cannons and take out the Pylon (thus shutting them down) and the few Dragoons that bother you; once that is clear, fly north straight over the base. Don't waste your time taking it out right now, you'll have a chance for that later.
There is a nice triangle of safe space above this base and below the EMP device. This is also the safest route to assault the device. The device is defended by a number of Photon Cannons, Dragoons, and Corsairs, as well as some Archons, but the units you really need to worry about are the one Arbiter and two Dark Archons; the most successful way to deal with them is to use your Corsairs as kamikazes. After laying Disruption Webs on the Photon Cannons closest to the edge, send the Corsairs into the base; the Dark Archons can mind-control two (better the cheap Corsairs than the expensive Carriers!) and the rest of your Corsairs destroy them. The Arbiter can then waste one of its Stasis Fields on the Corsairs. (If you're lucky, you might even be able to kill it before it gets a Stasis Field off; if not, you've at least softened it up for the Carriers.) After this, send the carriers in, keeping them as far northwest as possible, taking out Dragoons, Pylons, and Corsairs as you go. At the EMP device, rather than taking the time to destroy all six Photon Cannons, you can just take out the two Pylons and shut the cannons down. Once the attacking units are out of the way, the EMP device falls quickly. Purple has a lot of High Templar that can really ruin your day, but hopefully you already killed a lot of them when they tried to attack your base earlier.
With the EMP device gone, your new priority is to get your Carriers and Corsairs out of there – the area has no resources so it's useless to you, and it will soon be swarmed by Dragoons. Some Wraiths may come as well, and if you didn't bring an Observer, even one or two of those would be deadly. Unfortunately, by now the white base that you flew over is probably full of Dragoons (so full they can barely move around). This is where the Corsairs, once again, are a godsend: lay down a line of Disruption Webs across the edge of the base, and the Dragoons will just sit under them while your Carriers take them out. Once you've cleared out this base you can send in some Probes (several of your other bases have probably been harvested dry by now) and set up a Nexus and some photon cannons; this base might not have many minerals anymore, but it has a ton of gas (10,000 to be exact).
The Protoss are not totally finished off when you take out the EMP device. They are close, though; while they have several bases, both white and purple only have one more base each with Nexuses, so if you can take out the Probes and Nexuses you will cripple them. The white base in the center of the map is pretty easy taking (and has enough resources to last you through the remainder of the mission), just watch out for High Templar while you're attacking. Once you've destroyed the white base here, you can set up a base of your own. You might as well go crazy with Photon cannons (at this point you should have something like 3,000 minerals and 5,000 gas, and already hit the psi limit and gotten most of your upgrades, so why not?). Once you're ready, the purple Nexuses are more or less directly north of here. They will probably put up a much nastier fight than white did; purple still has Arbiters, Dark Archons, and absolutely ridiculous numbers of Dragoons and Dark Templar. Attacking with just your Carriers and Corsairs may not be enough; send over 12 Archons (which you should have started building around when the EMP device fell) right around the same time you start the air attack. You'll want your Archons (or whatever you send) to get there before the purple Dragoons start swarming the base, otherwise you'll be blocked off. Take out the Pylons or Photon Cannons that threaten you, and if the Dragoons come try to block them off at the choke point and use a combination of Disruption Webs and Carriers to take them out. If you got Archons into the base on time, you can divide the work – have your Carriers take care of the enemy units that are coming, while your Archons wipe out the Probes and both Nexuses. Once those are taken care of (make sure you do not leave a single Probe!) feel free to retreat if you're getting overwhelmed, which you probably are; the point right now was to cut off their production, not to wipe them out. Don't feel bad if your Archons get stranded and killed in the base; you can build more later, by now you should have almost limitless resources.
With the EMP device and the Protoss Nexuses out of the way, the hard part of the mission is over. You can leisurely work on rebuilding your army, upgrading whatever you still have, and wiping the remaining Protoss stragglers off the map. (White, whose last base is just west of the purple Nexuses you destroyed, will go out without a peep; purple will still have a lot of units throughout their large base which covers more or less the entire northern edge of the map, but by now you should be able to overwhelm them with sheer numbers.) Schezar's Terrans will still try to bother you, but as long as you have a couple Reavers or some Carriers near each base (to deal with Siege Tanks) you shouldn't have a problem – he certainly doesn't seem as dangerous now as he did during the early part of the mission where you're struggling just to stay alive. Once the Protoss are destroyed (you don't really have to destroy them entirely, or even at all – technically you could win the mission without killing anything other than the EMP device and Schezar – but it feels good to destroy every last one of them) you can focus on Schezar. Again, you don't need to destroy the entire red base, you just need to destroy Schezar (a yellow Goliath). You first find him in the small base at the east-central portion of the map, up on high ground (on the way, you can take out a small island with three Starports if you want to stem the flow of air units). When you attack that base, huge swarms of Marines, Goliaths, and Ghosts will descend upon it, and Schezar himself will get into a dropship and fly away during the confusion. Marines and Goliaths are normally pretty puny, but their numbers are so great here that they could actually destroy your whole fleet of Carriers if you don't bring support to bear, so make sure to get your Archons, Reavers, or whatever else you're using to the scene. Once you've gotten some space, you can go after Schezar again. The Dropship took him north, to the base in the northeast corner of the map. It's not all that well defended, and you can pretty much rush it head-on with all the units you have. Your forces should overwhelm the base so utterly and so quickly that you probably won't even see Schezar fall. When he does fall, however, you will get a message from Zeratul and the mission will end.