The first room of 0-4 should be somewhat familiar in structure if you played through 0-1 fully. After killing all of the STRAYS or all of the FILTH, another "somewhat" familiar FACE will meet you. The MALICIOUS FACE (hereafter referred to as Maurice) is now a common enemy. In this large room, he should be pretty easy to deal with, provided you kill the STRAYS first. One PROJECTILE BOOST should wipe out all of the FILTH. Quick tip, charging up a Sharpshooter shot and shooting the red bullets that Maurice shoots as soon as they are produced from his unmoving jaw causes them to explode and blow up in face. 99% of the time, this will instantly kill the Maurice, especially if the Sharpshooter hits the Maurice in the face as well as the bullets. Keep this one in mind, as you will see Maurice many many more times, and every time this trick will come in handy.
Now, as terrifying as this hall may look, you can actually just slide through this entire section without killing or touching a single enemy. The doors do not lock. This will skip all the way to the final room, which contains a few of the usual suspects. Be careful of explosives, because they will shatter the glass floor concealing a shredding fan. After the first wave of enemies is cleared, a horde of FILTH will spawn. This is a perfect opportunity to demonstrate an improvement on the jump/ground slam bait technology. Instead of ground slamming once the FILTH are gathered beneath you, loose a single Core Eject grenade. The blood from the FILTH will eliminate all damage you would have taken from the explosion. These are the last enemies you have to kill, so you can now make your way straight to the exit.
