As soon as you enter the level, aim towards the door to your right. An alien appears from it, so dispose of it quickly. Shoot the glass to your left and proceed through it into the next room. Here there is a Smartgun. Collect it, then keep repeating the process - smash the glass, move to next room , smash glass - until you reach the end. Here, use the jetpack to get yourself up to the next area, where you need to head for the open vent down below. Lower yourself down, then when you reach the next area, get yourself about halfway down with the jetpack, then fire a grenade at the floor. It should kill the facehugger below. Lower yourself to the floor, then go down any of three vents and shoot the grate at the end, before once again lowering yourself to the floor. Head for the sentry gun (you should be able to here it beep) and either use a bit of manoeuvring to get yourself past it (using the jetpack) or shoot it and then proceed. Whichever you use, lower yourself down the next vent. Get yourself through the fan to the floor quickly, then run through the door on the left, up the ramp and out the door into the corridor. Watch out, the Predalien will follow you and it has a brother nearby, but you should be able to disable both using a combination of both modes of the Pulse Rifle. In this corridor there are two doors at each end - two lead to single rooms with nothing in them, the others open up to reveal huge access shafts. Proceed through the either of latter, lowering yourself down to the next level. Go through the door and you will see a xenoborg - run past it and through either of the doors at the other end. Proceed down these corridors and through the other door, then collect the Sadar and the Medikit in this room and return to the xenoborg. Waste it, then you can collect the Armour in the right hand shaft. Return to the area where you collected the Sadar - you can reach these access shafts. Take the right hand one, and lower yourself all the way to the bottom. Proceed forwards, then on the right is a GrenadLacher. Collect it, then go either left or right and follow the passage round until you reach the main loading dock. Lower yourself carefully down to the floor, then enter either one of the pits to your side. In here, shoot the grate at the end, then carefully lower yourself down to the other end and shoot the grate there. Enter the room, then go out the door into the main corridor. At one end of the corridor is a door, at the other end is a very large ventilation shaft, which goes round in a circle, vertically. Enter the shaft and lower yourself carefully down to the bottom. NB: if you take too long entering the shaft, a Praetorian emerges from the vents above you. Shoot the grate below and fall or lower yourself to the floor. Walk towards the evac shuttle to end the level