Unlockable: Super Soviet Missile Master mini-game
Finish level 1-5 and the Super Soviet Missile Master mini-game will be unlocked
after the intermission sequence.

Unlockable: Minigames, Levels and Hats
Set the player 1 name to "ROYGBIV"

Hidden Hats
In the Options Menu, where you can rename your alien, use the following names to
unlock hidden hats for the 2 player game:
cletus
april
superfly
goodman
grrl
abe
princess
dandy

Unlockables: Head Gear
Area 51 Hat: Get to level 3-1.
Blond Hair: Beat the final boss using hard difficulty.
Diamond Tierra: Beat Level 2-2 using hard difficulty.
Jouster Hat: Beat Level 3-4 using hard difficulty.
Private Eye Hat: Beat Level 3-2 using hard difficulty.
Soviet Union Hat: Get to level 2-1.

All levels,mini-games&hats
Cheat code ROYGBIV