Unlock Everything
Enter your name as ENCHILADA!

Gate Rally Mode
To unlock Gate Rally Mode, you need to accumulate one win in Smack Attack Mode. If you've played, then you know this is not easy. An easier way to accumulate the one win you need is to plug in three additional controllers and play on the space level. The three uncontrolled opponents will always spawn on the upper ring around the level. This leaves them wide open for you to kill, but they're ignored by the CPU controlled players. You should be able to rack up enough points to win by killing these sitting ducks.

Invincibility
Enter CODY as a name.

All the Weapons
Enter name as "MELEEDEATH".

Get Whack Angus
Put in WHACKFAD as your name

Get Jungle World
Put in TWRECKSPAD as your name

Get Space World
Put in BRAINSALAD as your name

Get Ranged Weapons
Put in GUNSMOKE! as your name

Get Hazardous Weapons
Put in HAZARDOUS as your name

Get Count Earl
Put in COUNTDEAD as your name

Get Personal Weapons
Put in UNIQUEWPNS as your name

Get Pen & Ink Mode
Put in PENCILS as your name

Get All FMV's
Put in MULTIPLEX! as your name

Get Movement Power Ups
Put in MOVEITNOW as your name