Supertramp-school:
1. The gunshop one, well, we already all know about it.
2. The secret room.
First activate the trigger in the window in the toilet room, now do the first secret (Gunshop one), go to the alien shotgun and press e, you can become a god, leave the room, or kick the original god (but they can rejoin).
Paul308-base:
This button allows you to kill the god. Anyways, go in the base by any means, near the armory you will see a small box,
hold x and then press e. You will arrive in a small room, DO NOT press e on the door, it will put you on the roof of the small/rebel base. Press e on the only button, you will die, but the god also dies.
xnx-school:
If you hold into the ledge of the cafeteria and fall of, you end up into the gunshop!
More to come when i find out more secrets...