Part 45

Activate the nearby ceiling turret (a device that fires projectiles) and use it to attack aliens.

If the turret cannot see aliens, fire hornets (a type of projectile) through windows while crouched near the turret controls to hit them. The turret will fire at your hornets, keeping it alert.

After the first aliens are defeated, more will teleport in. The turret should eliminate some before being destroyed.

Use hornets to finish off remaining aliens, crouching for cover (a position to avoid enemy fire) to avoid return fire.

If firing hornets through windows is ineffective, crouch-walk to the doorway and fire hornets through the left end of the red railing, being careful not to be seen by alien grunts.

Once all visible aliens are dealt with, turn off the turret if it's intact. Approach the control room windows slowly, ready to shoot any remaining aliens.

Jump-crouch (a jump combined with crouching) through a window or jump over the railing to enter the control room.

Locate and collect the gauss gun ammo from wooden crates that were destroyed by hornets. Be aware of a potential alien grunt behind green crates to the left of the big ramp; use the crossbow to sneak-shoot it if necessary.

Go down the big ramp and turn right. Use altfire (secondary fire mode) hornets to destroy an explosive crate.

Fire regular hornets around the corner to hit vortigaunts in the next room, killing those in the open. For the vortigaunt hiding near the bottom of steps, either use hornets before it sees you or charge with a shotgun or assault rifle.

Use altfire hornets to shoot a glowing snark pod (a container that releases hazardous creatures) over a hatch. Once it breaks, run to the base of the big ramp and wait for snark noises to stop.

Use altfire hornets to destroy another snark pod down a path to the left of the ramp. Run to the hatch area to wait for these snarks to self-destruct.

Past the first snark pod's location, find a vine-covered side area with stairs. Bash through vines and destroy the snark pod at the top of the stairs. Dash to the safe hatch area and wait for the snarks to time out.

Return up the stairs to reach an upper walkway with a first aid station (a device that restores health).

Go back down the stairs and bash through vines to uncover another snark pod. Do not destroy it immediately.

Use altfire hornets to bash through vines past the pod, then use them to blow up explosive crates. The explosion will open the pod; run to your safe spot at the hatch and wait for the snarks to time out.

Past the blown-up crates, find a final snark pod near a ramp. Use altfire hornets to hit it and run to the hatch.

Return to the fenced-in side room near the top of the ramp. Push the fence door open.

Inside the fenced-in room, find an RPG (Rocket Propelled Grenade launcher) and a spare rocket next to a dead marine. Use the hornet gun's altfire to kill a barnacle (a creature that hangs from ceilings and attacks with a tongue) in a corner before collecting the snark pack underneath it.

Go down the ramp and look into the room beyond. Use altfire hornets to destroy the rightmost wooden crate you can see.

This reveals an alien grunt behind the crates. Fire regular hornets slightly to the right of the crates so they swerve into the grunt. As it moves, strafe left up the ramp to avoid its line of sight, continuing to shoot it with hornets around the corner until it dies.

Crouch-walk past the left side of two green crates, turn right, and approach the alien whoosh-thing (a device that propels the player).

The other grunt is behind a large stack of green crates. Quicksave (save the game state) and carefully blast it with two RPG rockets. If you take damage, quickrestore (load the saved game) and try again from a distance.

As the grunt dies, another will teleport in near the bottom of the ramp. Sneak-shoot it to death with hornets.

Bash open the remaining wooden crates with your crowbar to find supplies. Use the whoosh-thing to reach a narrow ledge with snarks and a health pack.

From the ledge, face the top of the green crate stack, run forward, and drop onto it. Collect the Crossbow and gauss gun ammo.

Drop to the floor, return to the fenced-in side room to resupply on RPG rockets, then go back to the hatch found earlier.

Optionally, dive into the water near the hatch to find a dead marine with an armor battery, two assault rifle clips, and AR grenades. Be aware of leech worms in the water.

Use the wheel to open the hatch and climb down the ladder to reach section c3a1a.

Upon reaching section c3a1a, shoot a headcrab (a parasitic alien creature) with your pistol as it appears through the ladder.

After exiting the ladder, pass through a red laser alert. Quickly move to a position where only the leg of a turret (a stationary automated weapon) is visible.

Shoot the turret down with your pistol after it finishes firing at a nearby headcrab.