Alien hominid

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 HatsSet the player 1 name to "ROYGBIV"Cheat:

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.