Map 1[edit]
After a few cut scenes the game begins. Don't bother searching the area, you won't find anything there. Head to the door and use the switch to reveal a microcircuit. Take out your hacking device and use it to open the door. Now you know how to handle your hacking device. Head in and the corridor collapses behind you.
Note: There are no enemies on this level. Some scripted horror scenes can give you a few gray hairs, environment sometimes can hurt you, also you can fall into bottomless pits if you're not careful. Other than that, there’s nothing to be afraid of.
Proceed further. The door ahead is locked, so turn left a see some guy's death. Walk until you come to a room with another creepy cut scene. Behind the computers on the right you can find two hanged bodies and one PDA with some info. Use it to read.
Note: You will find some PDAs and notes during the game. They can give you some plot info, but none of them is mandatory to read and they won't give you any items.
It looks like a dead end, but there is a trapdoor on the floor. Use it and drop down on some smashed car. Open the only double doors you can to find yourself outside. Something will kill two guys in front of you. If you want some pistol ammo, head left and use a box near some crates. There is also a drawing with some markings. Now you know the names of people recently killed before your eyes. Not like it affects anything.
Anyway, there is nothing more to find, so don't waste your time exploring this wide area. Head to the bridge. When you hear two shots, freeze and better make a step back. Something ahead will explode. After that you can cross the bridge. You can't open double doors, so head right. Don't bother exploring that area, nothing interesting there.
You will hear a scream and predator's clicking sounds. A man will fall down from the skies, dead. Creepy, but surprisingly harmless for you. Head forward as depicted in the textbook sheet before the bridge. It's hard to miss anyway. A car ahead will explode. Dive right or run forward not to get smashed.
The road ahead is straightforward. See two dead skinned bodies? Don't forget to pick up ammo for your pulse rifle under them. When you're ready, use the switch, then use your hacking device again and head inside to finish the level.
Map 2[edit]
Jut like the previous level, there are no enemies here, just a bit of hazardous environment. However, you may reload your weapons if you like.
Note: From now on you start each level holding your knife and zero ammo loaded to your guns. Switch between different weapons to reload them every time a new map is started. Aldo don't forget to switch to a different ammo type if needed.
Don't mind your radar. Look for a PDA near the crates next to a dot on the radar for more plot text. If you don't need it, head straight down to some technical tunnels. The road ahead is straightforward, just follow the corridor. You will see some white dots on the radar and hear wings flapping. These are the huge bugs. They can scare you all of a sudden, but they are completely harmless. Shoot them if you like.
Once you arrive at the end of the long corridor, pull the switch and head back. A pipe falling down can scare, but there's nothing to be afraid of. Just watch out for steam. Head up the stairs and proceed forward until you see a closed door. You can open it now. There's only one road ahead: left two times and open the smashed door.
You will appear in a big room with some computers and shelves. You can find pulse rifle ammo on the right shelf and some flares in the box near the right wall as well. Security alarm button does nothing. Call the elevator. Your radar will pick up some movement. Don't worry – it's just elevator moving and doors opening. Head up.
There is a table with blueprints on the right, but it looks more like some blue-and-white mishmash and won't give you any info. Two desks on the left contain shotgun shells and a PDA. Walk around the wall to see a huge landing beacon activation button. That's your current goal. Press the button and get back.
Your commander will be right in front of the door. Talk to him and take a grenade launcher from the box. Note the gates which are now open and an armored truck behind them. That's your next destination.
Map 3[edit]
From now on you will encounter enemies in the game, so stay sharp. Switch to different weapons to load them. Head up the ramp and through the door.
At the junction you will see a box, but if you were not wasting any ammo and flares, you won't find anything inside. To the right is a dead end, so head left. Another junction. To the right is a mess hall which you cannot enter yet. All you can find there is a note.
When ready, turn left on the previous junction (or walk ahead if coming from the mess hall) and the floor will crash. You can jump to where crates are and open a small chest there, but most likely it will be empty.
You will see some acid marks and a hole up above. You can get to the upper floor through the hole made by acid, but there is nothing of interest there. Just turn right until you come to two doors. The door ahead is locked, but you can find some pistol ammo next to it. The door on the left is your next destination.
There are an utility belt with flares and a first aid kit on the floor. There's nothing else interesting there, so go through the next door.
Note: If some ammo, health kit or other consumable lies on the ground, picking it up won't always make it disappear. You always pick up the necessary amount of goodies leaving the rest, if any, where it is.
The corridor left is barricaded, so go straight ahead. When you turn right, you will see a closed door and two pipes on the floor ahead. There is just a long corridor with nothing interesting ahead, so head through the door.
There is some ammo on the floor, don't miss it. Two desks near a huge bloodstain contain shotgun shells and a PDA. You next destination is down through a hole. If you like reading in-game texts, don't miss another PDA next to it.
When you jump down, try to land on a filing cabinet not to receive damage from falling. Creepy music will sound, but it's still safe. In a room with beds there is just one PDA and some flares, so jump down again.
The next room looks like a storage. Head out through the door. There is some pistol ammo on the right if you need it. You need to turn left and through the door, but don't get hasty. Turn left and ignore the door for now walking down the long corridor. Pick up a shotgun at the end of it. If you miss it, you will get it in the next level anyway.
Now head back and go through the door you saw earlier. There is a pulse rifle on the floor if you need ammo and a PDA next to a switch. When you're done scouting, pull the switch and hack the microcircuit. Mission objective complete, but now you need to get back. And now the fun begins. The first alien jumps down through the ceiling.
Note: All alien bodies create a puddle of acid when killed. Don't step into it or you'll receive damage. After some time all acid puddles disappear.
The second alien comes from the vent behind. That's your next destination. You need to crouch to get to the vent, but once inside, you can stand up to move faster. The road ahead is a dead end, so you need to turn left. Two aliens will jump down in front of you. The next road is straightforward, just be careful: two more aliens will appear behind you. When you come to a dead end, another and the last one alien in the vent shaft will appear.
When you jump down, make a few more steps to appear at the junction. First aid kit and a ladder up are on the left. That's where you need to go. If you need flares, turn right instead, but this will spawn an alien behind you.
When you're done in the vent, head upstairs and you will appear in a shower room. An alien will jump down from the ceiling. In the room you can find some pulse rifle ammo and dog tags near a dead body. You can find armor in a locker, but you need to hack it first.
When ready, go left to adjacent room and don't get scared by dramatic music. An alien is hiding behind big boxes and you cannot see it on the radar until it charges at you, so be careful. You can also find shotgun shells and a PDA.
As you go through double doors, you will find yourself on a set or stairs. Go up. On level 3 you will find a first aid kit. On level 2 you will find a box with pulse rifle bullets and a door you need to open. Be careful! As you step inside, a whole lot of aliens will charge at you. If you rush in headlong, you will find yourself cornered because those doors will close quickly behind you. It's perfect time to try out grenade launcher.
When you deal with foes, you will notice that the corridor looks familiar. The left way is a dead end, so turn right and go down the corridor fighting aliens. When you come to a junction, more enemies will appear behind you. The way left is shorter, the way ahead through the door and a set of already visited rooms is longer. Both are dangerous. Anyway, go up the ramp, head left and to where the level started.
Map 4[edit]
From here you can choose two ways to reach your destination.
The road left leads to personal quarters. Two aliens will attack you. These ones are brown and they always crawl and never walk straight. Go forward until you arrive at a set of huge crates. Look behind them for a box with rifle rounds.
The road ahead from the start leads to animal storage area. It will take you to a trash can where you can find just a notepad sheet and nothing of interest. If you turn left, you will encounter some aliens. After a fight pick up a shotgun near sealed double door if you haven't obtained it in the previous level. Don't forget to pick up armor and head up the crates to get over the fence.
No matter which way you took, you will find yourself on another road. Two more aliens will appear behind you. Go ahead, turn right and two more aliens will appear.
When you come to double doors, you can take a left turn with three skinned dead bodies. You will have to fight two aliens, but you will be rewarded with armor, a shotgun and a first aid kit. Just search this place carefully.
It doesn't matter if you scouted a dead end for goodies or not. Open the doors ahead, then other doors and move ahead. There is but a single road to the hive. Head in. Despite an eerie look, there is nothing harmful inside yet. Your dead comrade is glued to the left wall. You can use him.
Note: Using dead people glued to walls can sometimes give you ammo and other stuff. Sometimes an alien larva jumps out of their chest. You'll never know, so prepare something for close combat before searching those bodies.
Move ahead through the red-lit corridor. You will come to a big room and another corridor on the right. When you walk down the second corridor, an alien will attack you from behind. Don't forget to pick up pulse rifle ammo on the right. Doors are shut, so don't even bother.
Move ahead through a winding way until you see a narrow way to the left. Right ahead is a dead end with a first aid kit which you will most likely need. The way left leads to a door with three aliens ready to charge at you. Open it and prepare for a fight. Once you've done, pick up a health kit near a wall opposite from the elevator.
Head down using the elevator. In the next room don't forget to take ammo from the box on the right. Now proceed with caution. One alien egg is near the door, seven more in the room ahead. Use your pistol to save ammo for better weapons.
Note: Facehuggers are certain death. They hatch from eggs if you come too close.
Head forward picking up ammo near bodies plastered to walls. Your destination is a red dot. That’s the sergeant you need to find. Use her and she will tell you to kill her. It's impossible, so save your ammo. The only way for her to die is from a scripted scene. After that a chestbuster comes out of her and attacks you.
Now a really tough fight begins! Aliens will constantly spawn and charge at you. Run forward, shooting at them when they get close. However, there is a hint how to decrease the difficulty in that part. Don’t mind aliens and steam and charge to the elevator. Use the button to close the door. The less aliens will ride the elevator with you, the better. Kill them anyway. The point of such maneuver is to kill as little aliens as possible and to run away from the rest. The game won't spawn more aliens until some of the previous ones will be killed. You will still encounter enemies, but much less of them.
Run to the armored van to end the level.