Level 8: Final Outpost: 2 Secrets

First off, just play through the level normally until you grab the Chaingun. Once you have it, turn around and hug the walls to your left. You're looking for a hidden door. Keep searching, and you'll find it! Head through the door and follow the hallway until you reach a switch. Hit that switch, and then grab the goodies that appear: Shotgun Shells and a Backpack right in front of you. If you look around this secret area a bit more, you'll also find a Chainsaw, a Rocket, those super-rare Light Amplification Goggles, and a Medikit. Just be ready for some Lost Souls that like to hang out here. The exit switch is at the back of this room.

For the second secret, you'll need to progress further into the level until you find the Blue Key. Once you've got it, look for a water pit below you and drop down. In this watery area, make your way to the room on the other side of the pit. As soon as you step into this room, a lift will lower, which you'll use to get back up to the teleporter later. But before you do that, check out the small pool of blood in this room. Search the walls right next to it, and you'll uncover another hidden door. Go through it, and you'll find a MegaArmor waiting for you in this final secret spot.