Part 25

Climb stairs to reach a ledge for ammo. Hop on the railing next to the stairs, then run forward to drop safely past the electrified rail.

Move to the large doorway leading to the next area. Retreat and hide in the corner to the left of the doorway when you hear vortigaunts (enemy creatures that teleport) teleporting in.

Have your shotgun ready in case vortigaunts or marines enter your sight, but remain in your corner until the sounds of fighting cease.

Proceed carefully through the doorway and eliminate any survivors with the assault rifle. Be aware that one vortigaunt hides in a dark niche on the left side of the area.

Equip the crowbar and break the boards off the doorway on the left. Enter the room and switch to your shotgun.

Position yourself next to the security guard until a vortigaunt teleports in just outside the doorway. Quickly eliminate it with a double-barrel shotgun blast to ensure the guard's survival.

Destroy the boxes in the room to find .357 ammunition and health.

Guide the security guard into the room across the hallway.

Run towards the wooden boxes in this room to cause the ceiling to partially collapse, dropping headcrabs (small, jumping alien creatures). Alternatively, stay back and shoot the ceiling with your pistol.

Quickly retreat while your guard eliminates the headcrabs.

After the headcrabs are dead, go to a spot near the first aid station (a medical supply point) behind the wooden boxes. Turn around and throw a hand grenade into the ceiling area to kill the remaining two headcrabs.

To reach the ceiling area, jump-crouch onto the single box, then jump-crouch onto the two-box stack, and finally jump onto the ceiling ledge.

Search the back of the ceiling area for three armor batteries (items that increase your armor capacity).

Drop back down to the floor. Break the boxes to find another armor battery. Use the first aid station if needed.

Hit the guard with your crowbar to acquire his pistol. Quicksave (save your game at a critical point) before proceeding to the other end of the area.

A marine (enemy soldier) is manning a large gun protected by sandbags. To defeat this marine, run and stand behind the large wooden crate on the right until the gun stops firing.

Bash the crate with the crowbar, then immediately run forward and jump over the track. You may get shot, but you can then move next to the sandbag pile and jump to see and shoot the marine manning the gun.

Alternatively, to safely take out the marine, get behind the large wooden crate on the left. Crouch-strafe (move sideways while crouching) slowly to the right until you can see the right edge of the gun.

Toss a hand grenade or AR grenade through the gap to the right of the gun to destroy the marine. Quicksave before throwing the grenade to avoid wasting ammunition.

Once the gun is disabled, jump to its side of the track if you are not already there. Jump onto the slanted cement beam that leads to a horizontal crossbeam.

Jump-crouch onto the crossbeam, then jump to a narrow ledge. From this ledge, jump onto a beam with an armor battery.

Slide carefully down the slanted beam on either side. Move along the ledge next to the track until you reach the large red "BLAST DANGER" doors.

After the doors open, back up to a safe distance. Use your pistol to detonate one of the tripmines (explosive devices triggered by proximity) set just past the doors, or carefully crouch-walk under them.

Past the doorway, crouch-walk slowly towards the top of the ladder. Observe the walkway below for a marine.

If you are careful, you can sneak-attack the marine with the .357 Magnum before they spot you.

Climb down the ladder and proceed through the doors near the marine to find another rail car.

Search the room to the right to find a health pack and .357 ammunition in a wooden crate.

Check the area just past this room for a hidden HEV station (a device that replenishes your suit's power) in an easily missed wall niche.

Board the rail car and ride it forward slowly, crouched and pressed against the control console.

When between the two red laser alarm beams, stop the car and stand up briefly to locate a bullsquid (amphibious alien creature) positioned ahead.

Use shoot-and-duck tactics with the .357 Magnum to eliminate the bullsquid.

Slowly move to the right on the rail car to sneak-attack a bullsquid on the walkway to the left.

After the second bullsquid is eliminated, crouch-ride the rail car until it reaches steps on the right.

Exit the rail car but do not ascend the steps. To avoid activating the turret (an automated weapon), jump onto the railing to the left of the steps.

Crouch-walk along the railing until you are well past the turret.

Collect the AR grenades located near the dead bullsquid.

Use the rail-walking trick to return past the turret and onto the rail car.

Ride the rail car forward until you reach a ledge on the left with a turret and a door.

Stop the rail car and open the door. Be ready to shoot the bullsquid beyond it with a .357 Magnum slug and strafe left to avoid its toxic spit.

After the bullsquid is dead, move slowly into its room. Use your pistol to sneak-attack a headcrab hiding around a corner on the right. There is a chance another headcrab is past the door on the left, though the bullsquid may have already killed it.

Go to the back right corner of the room and use your crowbar to kill the barnacle (a hanging, tentacled creature).

Search the room for supplies before returning to the rail car.

Ride the rail car onward to the area designated as section c2a2e.

As you round the corner into section c2a2e, crouch and move slowly.

Strafe left off the rail car without stopping it as soon as you are past the corner.

Wait and observe the rail car continuing onward.