Part 42

Switch between your assault rifle and hornet gun using the "Last weapon used" key.

Approach corners slowly to sneak-shoot enemies like vortigaunts with hornets.

After clearing the initial enemies, collect health and bullets near the mounted gun.

Use the alien whoosh-thing (a device that launches you upwards) to reach the higher floor. To use it effectively, run towards it while facing your desired direction and jump as you land on it.

Once on the upper floor, turn right and crouch-walk until you hear fighting below.

Wait for the fighting to cease, then use the hornet gun to sneak-shoot any survivors. Use the assault rifle to finish off any remaining enemies.

Drop back down to the lower floor with the whoosh-thing.

This is your final opportunity to revisit the two guard-opened supply rooms.

Use the whoosh-thing again to return to the upper floor.

Look into the lower area where the fighting occurred. If the vent shaft entrance near the back right corner is covered by a grating, shoot it with altfire hornets until it breaks.

If snarks (small, aggressive creatures) emerge from the shaft, wait for them to explode before proceeding.

Crouch down at the vent shaft entrance. Use your flashlight to see the back wall and shoot it with altfire hornets until it breaks.

Quickly run and hide behind the health pack crates to avoid the released snarks.

Wait until you no longer hear snark noises or explosions.

Return to the vent shaft and proceed until you reach the broken-open area. Enter it to collect snarks.

Continue down the shaft past the snark collection point until you encounter a grating.

Bash the grating with the crowbar.

Turn and backtrack around the corner as marines destroy part of the shaft.

Get out your snarks and quicksave (a manual save point).

Turn the corner and toss several snarks through the shaft opening to attack the marines below. If snarks are not thrown, quickrestore (load the quicksave) and try again.

Once all marines below are eliminated, return to the snark stash to resupply.

To drop into the garage area without taking damage, crouch-drop onto the back fender of the raised car, then to the floor. Alternatively, drop and use the first aid station to heal.

Collect the three armor batteries if needed.

Open the garage's small door and immediately retreat to the other side of the garage to avoid explosions and rubble.

After explosions create a hole in the wall to the left of the door, quicksave.

Toss snarks through the hole. If marines fire AR grenades, stay close to the hole to avoid them. Alternatively, jump-shoot hornets through the hole or through debris holes past the small door.

If snarks or hornets are ineffective, shoot a marine with the pistol through the debris holes.

Use the method described below to elevate yourself, then hit any survivors with RPG rockets.

Once both marines are dead, use the two hanging control switches in the garage to find the one that operates the empty lift.

Hit the control switch again and run onto the lift before it rises.

To pass through the wall hole, run onto it from the raised lift without jumping.

In the outdoor area, use the huge gun emplacement to destroy the nearby metal door.

Continue firing at the doorway until alien grunts stop appearing.

Go through the doorway and down to observe marines fighting aliens.

Use the hornet gun's altfire mode to quickly kill the vortigaunt on the same walkway.

Retreat out of sight.

When the fighting stops, quicksave.

Return to a position where you can see into the room below.

Sneak-shoot any remaining alien grunts, or use the gauss gun if necessary. If they are not visible, they are likely in the side room below the walkway.

Follow the walkway to find a ladder and climb down to kill the grunts.

Check the side room for needed items, including gauss gun ammo inside an open metal crate.

Climb back up the ladder.