Half-Life/"We've Got Hostiles!"
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"We've Got Hostiles!" will most likely be the first real challenging level for almost everyone. It's about the size of Unforeseen Consequences, and introduces a worthy adversary, the HECU (Hazardous Environmental Combat Unit) Grunts. The HECU Grunts are human footsoldiers who know how to work together, flank, and use a lot of tactics. "We've Got Hostiles!" takes place across several Black Mesa industrial facilities.
As soon as the elevator doors open, exit and turn right. You'll immediately see a scientist pleading for the blast door to be open. However, his plea doesn't end up being taken care of, as the security guard in charge of the door gets dragged away by a zombie. The scientist runs off...directly into a laser mine. You'll notice several of these laser mines throughout the entire stage (the mines give off blue lasers in whatever direction it is facing), and as soon as you step over them, they'll explode. You can also shoot the base of the mine (the black part) to make it explode, as long as you're a good distance away.
Next to the large blast door is a health station and the first HEV charger you will see. Charge up your suit until the HEV charger depletes (you'll seriously need it for this stage) and use the health station if you want. Since there's no where else to go, proceed down the hallway where the scientist ran off to.
You'll immediately see some red lasers as you turn the corner. These red lasers (don't get them confused with the blue laser mines) will trigger a nearby turret, so avoid stepping over them when you can. You cannot however, jump over these red lasers, so you'll have to run right through them. Go as fast as you can to the other side of the room where the red firedoor is. Avoid picking up the MP5 SMG in the corner because you'll just lose valuable health in the process (you'll pick one up later anyways).
Whenever you see one of these red firedoors, always smash the nearby activation switch (unless otherwise noted), as it will block many enemies from coming through. In the next passageway, jump over the laser mine and then crouch under the next one. This passage leads to a lounge, and as soon as you walk past the soda machines, two Vortigaunts will spawn in the checker-tiled room. Kill them immediately with your Shotgun and use the nearby health station if you need it.
Proceed down the next passage on the left, and jump over the red laser at the intersection. This room has four turrets inside; two directly in front of you when you enter and two on the other side. A Vortigaunt will then spawn behind you, so kill it quickly (make sure he doesn't run over the red laser though). Avoid destroying the nearby turrets because you'll never come back to this area (if the turrets were activated, just throw a well-placed grenade in between the two, which will destroy them in no time). Smash the first large crate next to the green boxes to pick up five grenades.
Now walk up to the green boxes and keep jumping until you reach the top. Before dropping down, take out your shotgun and go to the very right side. Destroy the turret directly beneath you with a well placed double-barrel blast and then jump down. Run as fast as you can to the fire door and smash the nearby activation switch and jump up on the pile of green boxes in the next room.
Before dropping down, I advise you save it, especially if you have the Source version. Make sure your shotgun is out, and then drop down. Be careful though, because the floors are very slippery and there's a slight chance you'll fall into the elevator shaft. Two turrets wait around the corner, so jump over the trigger lasers as best as you can, and if you activate them, immediately run forward to the two turrets and fire double-barrel blasts at them. When both turrets are down (if the scientists survived, there's no use for them, so just leave 'em there), shoot the laser mine in the next room to destroy the other ones. This explosion may or may not activate the fire door switch, so run into the next room if it does. Collect the pistol clips, shells, and batteries in the next room and then climb up the ladder.
Walk across the platform, and before you go up the next ladder, smash the nearby crates for a battery. Now climb up the next ladder and walk across the next platform. Before you enter the next room, you may want to save your game, because you're about to encounter the first HECU Grunt. As soon as you walk in the room, a scientist will run down the flight of stairs. Use this distraction to deliver two double-barrel blasts to the soldier's head, and grab his MP5 if you didn't do so in the beginning. There's also two clips of SMG ammo in the corner, so don't forget to grab them. Now press the elevator switch and step inside. Save the game as the elevator goes up, and take out your MP5.
When the elevator doors open, a scientist will blindly run forward...not making it very far. Ok, this will be your first major battle against the HECU's. The most important tactic to apply here is to find cover, peek out, fire, and find cover again. If you run down the left passage directly to your left, you can shoot the explosive barrels in the distance to hopefully kill the first grunt. Draw the other two out, find some cover, and apply the tactic listed above. If they throw any grenades in your direction, run away as far as you can (but make sure you're still behind some type of cover). I recommend the MP5 to take these guys out, but only fire it in short bursts to ensure accuracy.
When all three Grunts are down, use the HEV charger and health station way in the right corner. Climb up the stairs and go through the open fire door (you don't need to smash the activation switch). Walk across the platform and into the next hall, avoiding the Barnacles. Avoid the passage on the left, as we'll go there soon.
Take a right from the intersection, which leads to a room with another pile of green boxes. Jump up these boxes until you reach the top. Now you'll have to jump from the top to the conveyor belt. The belt is moving in the opposite direction, so you'll have to really move forward to continue on. When you get to the other side, drop down and use the HEV charger and health station, and then grab the MP5 ammo right next to them. Jump to the top of this pile of boxes, and then jump on the conveyor belt.
When you reach the other side, take out your grenades, because there's a HECU Grunt behind the sandbags up ahead. Quickly throw one of your grenades behind the sandbags and find some cover. The grenade will instantly kill the soldier (if he survives, just gun him down quickly). Use the health station in the corner if you want, and save your game.
When you look down below, you'll notice several red lasers and a turret. Shoot the turret with a double-barrel blast, and look at the fire door. You'll notice a laser mine right behind it. Shoot the laser mine and quickly drop down and run through. This leads to a large storage facility, where five HECU Grunts preside (so save the game). Two scientists will run forward, and like all the others, not survive. Now if you look up, you'll see a platform. One of the Grunts should be stationed there, so kill him quickly with your MP5 SMG. Another may or may not go across the platform, but if he does, gun him down as fast as possible. If you keep going forward, the Grunts will actually come to you, so stay on the ground floor for now.
You'll notice a Barnacle at the top of the first staircase. Do not kill it, as a Grunt will actually be dumb enough to walk right into it. From the ground floor, just keep firing your SMG and finding cover. Although the Grunts have the height advantage, you have the advantage of finding some quick and easy cover behind boxes. Remember to fire the SMG in short bursts to the head to ensure a quick kill. Once all of the Grunts are down, proceed up the stairs and grab the shotgun shells next to the sandbags. Go up the next set of stairs and follow the walkway until you reach another set of stairs. These stairs lead to a nice health station and some ammo. There is a Barnacle that's hard to see in front of the health station, so kill it before you replenish your health (the Barnacle will instantly kill you because it's so close to the ground).
Now go back down the staircase and take a right down the next passageway. Avoid the Barnacles and go up the ramp. Save the game, because the next room has three HECU Grunts. Collect the grenades nearby, and start throwing them down below (in the middle). Hopefully you'll kill some of the Grunts with your grenades, but if you don't, just take out your SMG and start shooting them. Once they're all down, smash the wooden boxes that are nearby for a battery. Go down the staircase that's to the left (do not fall down or it will lead you all the way back to the room with the lone Grunt behind the sandbags). Smash all of the wooden crates where the Grunts presided to collect some batteries and medkits and use the nearby health station if you need to. Once you collect everything and are good to go, press the elevator switch and head on up.
Save the game as the elevator is going up, because there's going to be a tough battle up ahead. Take out your grenades and immediately run to the left. Start throwing your grenades into the group of Grunts as fast as you can to take them out. As soon as you are out of grenades, take out your MP5 and start shooting, applying the same tactics you have learned. You need to kill these Grunts as fast as possible or all of them will come to you, and you do not want to fight them in a small room like this one. If they do come inside, take out your shotgun and start shooting as fast as possible. Once they're all down, use the health station in the corner and save your game. Now run out into the open area and go to the open door that's in the middle. The V-22 Osprey plane above you is dropping off bombs left and right that will instantly kill you.
Save the game again when you're inside the small passageway. Go down the ladder and smash the crates that are in the corner for some medkits and ammo. Use the HEV charger and health station and open the door. The Osprey is starting to drop off soldiers inside the complex. Keep jumping down and landing on the small platforms below until you reach a large vent shaft. Run as fast as possible through this vent shaft, and you won't have to worry about HECU Grunts anymore.
