Level 4: Holding Area: 2 Secrets

First things first, play through the level normally until you reach the Blue Door. You know, the one that usually leads to the exit? Don't worry about the Blue Key; we won't need it for this secret. Now, turn around so you're facing away from that Blue Door. Look to your left, and you'll spot a computer panel next to a staircase. Interact with this panel, and bam! Two doors will slide open to your left. Inside one, you'll find four Rockets, and the other holds a Soulsphere. Keep an eye out, though – on higher difficulties, some Lost Souls like to hang out in here. Just step into either of these newly opened rooms, and you'll get credit for your first secret.

Okay, with the first secret bagged, turn back around. You should see four switches in front of you. Here's the sequence: hit the third switch (that's the second one from the right), then the first switch (the one all the way to the left), followed by the second switch (second from the left), and finally the fourth switch (all the way to the right). Do that right, and all the pillars in front of you will level out. Now, turn around again and open the door you see. Head through it, and you'll find yourself facing a teleporter. Step into it. You'll pop out in front of those same four pillars, but now they're your path forward. This part can be a little tricky, so get ready to move. You'll need to strafe and run across all four pillars to reach the opening on the other side of the room. It might take a couple of tries to get the hang of it, but once you make it across, head into the larger room. That's your second secret! The exit switch is also in here, and it'll whisk you away to Level 29: Outpost Omega.