E1, M7: Computer Station
This level has 4 secrets and 2 extra hidden areas that give bonus items.
Secret 1
In one area of this map, you walk up some steps to find a walkway over a sea of slime. When you enter this room, a pillar will drop down in the center with some enemies on it. When you walk onto the pillar, it rises up.
Turn left and run into the slime. There you will find a platform with a chain gun on it. There is also a secret door there that leads to a backpack, and yet another secret door from that area that lets you out of the slime.
Extra Area 1
The same pillar that you used to get to secret 1 leads to the next few secret areas. This time turn right and run into the slime. Near the wall is a raised ledge. You can find a hidden automap on it.
Secret 2
Fall into the slime pit that the ledge with the automap is next to. There is a tunnel with a biohazard suit. Next to the suit you will discover a wall with a red button. The red button opens a secret room with a switch inside. Press the switch to be able to find a chainsaw later in a different part of the map.
Extra Area 2
In the slime, past the biohazard suit, you will come across a brown pillar. There is a blue armor in a small indentation in this pillar.
Secret 3
At the end of this giant pool of slime is a soulsphere on a brown platform. Collect it to find a way out of the slime.
Secret 4
Once you have the blue keycard, head back to the yellow key door room. A little area full of enemies has opened up there. This new alcove contains a secret door that leads to the outside courtyard and a blursphere.