Area 51 Cheats

Right before you are about to experience an in game cut scene (doesn't work on
movies of course) push up on D-pad to change into mutant form and then activate the cut scene to view the cut scene in mutant vision.

In the stage Life or Death, there is a small key on a dead soldier in the damaged lift where Cole starts the stage off at. Grab it to open the small lockers in the stage. One of the small lockers in the first power conduit pit has a databank item that upgrades the alien grenade (it now homes in on enemies).

In the level "The Grays" proceed into the 4th room in the level, where you can see the monorail you entered the level from out the window. Push the computer console there and it will say "Lifter Engaged". Make your way back outside to the monorail, you can now stand on it. Run all the way to the back of it and you will be warped to a weird room with sharks that have machine guns attached to their heads.

If you kill all 3 sharks (I used the BBG, about 7 bursts each), a wide array of goodies appears on your way back to the monorail: Health, Ammo, JB Grenades and a Meson Cannon (The Alien Rocket Launcher).

Once you return through the portal back to the bay area, do not try to get back on the monorail, or you'll be instantly killed!

Find and scan all five databank items in a level to unlock the secret of that level.The final secret of the game will be unlocked when all prior secrets have been found.