Part 47

Destroy the large door ahead of the tank. This will cause alien grunts and vortigaunts to teleport in.

Strategy 1: Get on the side of the tank just above its ladder. Quicksave. Fire the cannon, then immediately back up against the nearby wall. Turn right and run along the wall to the walkway's ladder, then climb it quickly. Run past the bottom of the stairs in the previous room before stopping. Wait, then crouch-walk back to the repair bay's entrance and use the hornet strategy against the aliens. If alien grunts fire hornets, run back past the bottom of the stairs and wait before returning. (Vorts cannot zap you through the walkway.)

Alternative Strategy: Crouch behind the tank's open hatch. Fire the cannon, then look left and use the machine gun without changing position. Watch for vorts and grunts to your left and shoot them before they reach you.

Alternative Strategy 2: Back up to fall to the floor behind the tank, ensuring no alien grunts see you. If a vort sees you, wait with the assault rifle out for it to come after you. Move against the wall and jump-fire hornets over the tank until the two alien grunts are dead. Try to kill all vorts. Peek around the left side of the tank to check for missed enemies (one may be behind red tool cabinets).

After all enemies are dead, drop down and go toward the door you blasted with the tank. Stay on the right side of the passage and crouch-walk forward while looking left until you see part of the ray gun's base. Fire regular hornets toward the gun to kill the two grunts behind it. (Destroy the ray gun before horneting the grunts.)

Get out the crossbow and slowly crouch-strafe to a position where you can see the ray gun but it cannot target you. Shoot it with darts until destroyed.

Turn to deal with the final alien grunt to the right. Sneak-shoot it with the crossbow until it is dead.

Turn back toward the destroyed ray gun and run toward it to avoid a collapsing wall.

Before going past the ray gun to find the exit door, collect one health pack and two armor batteries.

Return to the repair bay and climb its walkway ladder. Go back down to the bottom of the stairs, then move forward and left to find a large yellow machine. Bash the wooden crate near the machine for a health pack. Find an armor battery at the back of the narrow, dark passage on the right side of the machine.

To get the other armor battery, go back to the big toxic waste spill near the elevator. Crouch-walk carefully along the safe path between green waste until you get near another large yellow machine. Jump over toxic waste to the machine's right side, then crouch-walk carefully onto the machine's narrow rim. Use the rim to cross to the machine's left side (where the armor battery is), then back to the machine's right side. Jump over the toxic waste again and crouch-walk back to the safe area.

Go back to the repair bay, then past the ray gun emplacement to find a large door with a button panel on the left wall. Use the panel to open the door.

Go past the door and use the big yellow button on the left wall. The "Lambda Core" chapter will start.

Lambda Core - BIG LIFT AND ASSASSIN ROOM: Go through the big doorway and up steps on the right. Enter the small control booth and use its button.

Run over to the big lift platform with the truck on it. Stay toward the back on the right side of the platform as it descends.

When the lift stops, use the hornet gun's altfire to shove the nearby small wooden crate aside so you can hornet-kill a headcrab. (The crate won't move, so destroy it with altfire hornets to get at the crab.)

Destroy the crate with altfire hornets if you haven't already. Get out the Crossbow and edge carefully to sneak-shoot a bullsquid spitting at a headcrab on top of crates.

After the bullsquid is dead, use the hornet gun to kill the three crate-top headcrabs. Look behind the nearest stack of green crates to find one last headcrab to hornet.

Alternative (Lift): Stay on the lift and hornet-kill the three crate-top headcrabs from there, plus any floor-level headcrabs that come within range. If the bullsquid runs into view, quickly kill it with the assault rifle or shotgun. If not, sneak-shoot it with the crossbow. After it is dead, look around for more floor-level headcrabs if you only killed one or two before.

Use the crowbar to bash all wooden crates for supplies. Use the yellow ladder in a corner to climb up to a first aid station and pick up shotgun shells and hand grenades.