Eradicator/Mazrium Extractory (F4)

This level is in three main sections, each with a main objective. You begin in a storage room above the first section. Outside and down the hall there's a room with a console and a small door: inside the door here is the main power switch to the machinery in the first section.

Four crushers--fast!
Throughout the first section is a long meandering conveyor with four crushers spaced throughout. Somewhere near each crusher is a switch that deactivates it, and a compartment with a repair droid inside. First, explore this whole area, down to where the conveyor ends (beyond here is the second section) and eliminate the enemies. This will give you an idea of how this area is laid out. While you're at it, flip one of the switches to turn a crusher off. The nearby repair droid will come out and reactivate it after a minute. They're numbered 1 through 4, in beginning-to-end order along the conveyor. Note in particular where each switch is. The switch for crusher 2 is in the meandering corridor that goes through the area, rather than near the conveyor in the factory areas like the other three. Also, those octagonal windows can be destroyed like air vents, allowing you to jump through.

The main objective here is the most time-sensitive in the entire game, and can be very difficult depending on your skill at games like this: you'll need to very quickly get all four crushers turned off before repair droids can get any of them reactivated. Unless you're incredibly expert at this sort of thing or (and?) have become highly familiar with the layout, you'll certainly need several tries before succeeding. Try doing a few run-throughs first without hurrying, and get a route planned out. Also, be careful not to step into a crusher while it's still on: it activates by sensor when something goes through it and you'll get crushed (what a concept!). One idea is to start with crusher 1, go up the steps around the corner to where it crosses over the conveyor, follow the conveyor here to crusher 3 (the one with the switch next to it), then jump up on the bridge nearby to the corridor and downstairs to the switch for crusher 2, then out to crusher 4.

When you've succeeded in getting them all off, go back toward the level entrance to that room with the console and door. Hit the big switch inside the door to complete your first objective. (You don't need to rush to this; once you get all the crushers off before any can be reactivated they'll be left alone.) Before continuing, there are two secret areas in this section. Look for and activate a half-height console on the wall near the repair-droid compartment for crusher 2 (the one in the corridor): there's a secret area behind it with a Secret Level Access Keycard. Next, follow the conveyor to near the end, where it passes a quality-control checkpoint (the purple section). Follow the chute down to a disposal room, and look for a misaligned texture on the wall. There's a secret area here with some items.

Grinders
When you're finished in this section, go to the big room near the end of the conveyor, through the door and to the next section. In here are three Mazrium grinders you'll need to shut down: your second objective. You'll see some overhead platforms with a bunch of high-end items and ammo. Collect these by means of the Mazrium platforms before you shut down the grinders, otherwise you won't be able to get to them except maybe with Low-Grav Boots. Go to the far end of the room and follow the raised walkway to the end. That red flickering device behind the grate powers the grinders, but you can't reach it from this side. On the wall directly opposite the grating there's a secret door and area.

Go to the next room. You'll see the Mazrium silos, and floating platforms with refined-Mazrium tracks along the floor and ceiling. Shoot out the vent by the door and follow the air duct, which leads to the red flickering device. Destroy it to shut down the grinders and complete the second objective.

The pretty purple goes kaboom
Go to the room with the Mazrium silos again. This is a seeming dead-end except for the three vents up on the wall. (You can reach these if you jump from the Mazrium tracks. You don't have to wait for the platforms.) There's a big convoluted network of ducts and they don't show up on the automap, but it's not complicated. Go to the right-hand vent and follow the air duct until you reach a T-junction. The right-hand way goes to the other side of that double-chamber you just passed by if you want the missiles. Go left, and you'll reach a room with a chains/sprockets machine and three additional ducts. The right-hand path eventually goes to the left-hand vent back outside, and there's a Detonation Mine in case you ran out. The left-hand path dead-ends in a small room with an enemy and an item. Take the center path, which leads to the Mazrium silos. The mines in the duct are Detonation Mines you can pick up, not a booby-trap. Activate the silver wall to the left for a passage back to the room--this counts as a secret area.

Break the octagon-window and go inside the silo. Enjoy that cool purple texture for a bit if you like. Now, place a Detonation Mine (#8 ammo) inside the silo, get away from the silo and up the duct or out to the room, and detonate the mine. This will destroy the Mazrium in the three silos in a chain reaction. Your objectives in this level are now completed. (A little technical aside: the destroyed silo is one of the few places within the game where surface textures are changed during gameplay, aside from stuff that becomes broken or damaged when you shoot at it. This is one of those higher-level capabilities that unfortunately is only part of the level DLLs and not something you can do in the level editor. Check out the Level-editing page for more on this.)

Before leaving, go back to the silos. Go to the silo at the far end, and activate the far wall for a secret area. Also you'll probably want to explore the network of air ducts some more--this is one of the neat parts of the game. Be sure to go to the middle vent; there are a couple small rooms with items including a Geosurvey (this doesn't show the ducts, though). When you're finished, go back to the room with the grinders. Up in the corner at the end of the room with the corridor to the first section, there's a small door that was covered up before. Jump on the grinder, then to the console, then up to the door. Jump down the drop chute inside to exit the level.

Secret Level Alert
This episode's secret level is accessed following this level. If you have collected four Secret Level Access Keycards thus far, you'll go to Waste Transfer (FBonus) next. Otherwise, you'll continue to Warehouse X-14 (F5).