Destroy All Humans!

Bulletproof Crypto (invincibility):
Pause game play while playing as Cryto, then hold L and press X, Y,
Left(2), Y, X, then release L while the game is still paused. A
message will confirm correct code entry.

Ammo-A-Plenty (unlimited ammunition):
Pause game play, then hold L and press Left, Y, White, Right, Black,
X, then release L while the game is still paused. A message will
confirm correct code entry.

Deep Thinker (unlimited concentration):
Pause game play, then hold L and press Black, White, Y, Right, White,
Y, then release L while the game is still paused. A message will
confirm correct code entry. 

Pox Unlocks (all upgrades):
Pause game play while on the Mothership, then hold L and press X, Y,
Left(2), Y, X, then release L while the game is still paused. A
message will confirm correct code entry.

Nobody Loves You (reset alert meter):
Pause game play, then hold L and press White, Right, White, Black, X,
Right, then release L while the game is still paused. A message will
confirm correct code entry.

Aware Like A Fox (full alert meter):
Pause game play, then hold L and press Right, X, White, Black, Right,
White, then release L while the game is still paused. A message will
confirm correct code entry.

Mmm... Brains! (increase DNA):
Hold L at the Mothership's main menu and press Black(2), White(2),
Left, Right, Left, Right, White, Black, then release L. A message
will confirm correct code entry.

Alien From Ipanema mode:
Pause game play, then hold L and press Y, Black, Left(2), White,
then release L while the game is still paused. A message will
confirm correct code entry.

Monkey Brad mode (annoys FlexMentallo):
Pause game play, then hold L and press White, Right, Left, Black, Y,
White, Black, X, then release L while the game is still paused. A
message will confirm correct code entry.

I Told U I Was Hardcore mode:
Pause game play, then hold L and press White(2), Right, X, Y, Black,
White, Black, then release L while the game is still paused. A message
will confirm correct code entry.

Helvetica mode:
Pause game play, then hold L and press Black, White, Black, X, Black,
White(2), then release L while the game is still paused. A message will
confirm correct code entry.

Blind Humans:
Pause game play, then hold L and press White, Black, Right, Left, X,
Black, White, then release L while the game is still paused. A message
will confirm correct code entry.