SECRETS

1. In one of the storage rooms with all the crates, there is a recessed ventilator panel in the Western-most wall. Shoot it, and climb the crates to reach the secret area behind the panel. [In vanilla DooM2 climbing the last set of crates is tricky, but is definitely possible. If you're using a port that supports jumping, simply jump to the top-most crate, and save yourself a little bit of frustration.]

2. In the area to the West of the map (the part with the brown slime), go outside, but do not jump down to the ground. Go around the balcony until it ends in a differently-textured wall. Press on the wall to access the secret area.

3. After picking up Secret #2, above, return inside and turn right at the UAC door. Follow the curved corridor until it comes to a computer area with alcoves containing enemies, with imps on the right side. One of the alcoves on the right contains a mini-boss (Hell Knight on Skills 1/2 & 3, and Revenant on Skill 4/5). Press on the slightly recessed computer panel behind the mini-boss to reveal the secret.

4. After picking up Secret #3, above, continue Eastward. You'll pass a doorway to your left, but keep going until you come to the darkened area. Turn left and go through the UAC doors, and turn left again. The room you enter has a differently textured wall in the far left corner. Shoot it to reveal the secret area.