macetes para area 51??? 10 points?

Final Secret:
Find all the secrets in game to unlock the last secret.

Unlock hard difficulty:
Finish the campaign mode in medium difficulty mode.

Unlock Alien avatar in multi-player mode:
Finish the campaign mode in hard difficulty mode.

Invincibility:
Pause game play, the press X, Circle, Circle, Triangle, Circle, X.

Start with a shotgun:
Pause game play, then press Triangle, Square, Triangle, Left, R1

Level skip:
Go to the main menu. Choose “Arcade”, then aim at the black border
of the boxes with “Warp Ahead” or “Beginning” to begin farther
into the game than normal.

Non tested cheats, need your confirmation!

100% health all the time:
During gameplay, press R1, R2, L1, L2, Left, Up, Down

100% ammo all the time on any gun:
During gameplay, press R1, R2, R3, Left, Right, Down

XM-32 viper assault rifle:
During gameplay, press Left, Right, Down, Left, Right
Submitted by: Karl

God mode:
Pause game play, then press Up, Down, Up, Down, Left,
Right, Left, Right, Down