While playing the game, hold LB + RB + Up which will enable Big head mode.
Brian The Brain and Space world
Enter the character selection screen, select "Load" then enter "BRAINSALAD" as a name to unlock Brian The Brain and Space world. Alternately, win Smack Attack, Gate Relay, and Flag Relay in all three levels of the Space world.
Cheat mode
Enter "PITA" as a name to unlock all cars, tracks, and modes except plastic mode. Enter "SUSIE!" as a name to unlock all cars, tracks, and modes including plastic mode.
Count Earl and Transylvania world
Enter the character selection screen, select "Load" then enter "EARLSPLACE" as a name to unlock Count Earl and Transylvania world. Alternately, win Smack Attack, Gate Relay, and Flag Relay in all three levels of the Transylvania world.
More Codes
Enter the character selection screen, select "Load" then enter the below listed names.
Effect
Code
All FMV sequences
MULTIPLEX!
Hazard weapons
HAZARDOUS
Melee weapons
MELEEDEATH
Movement power-ups
MOVEITNOW
Pen and ink graphics
PENCILS
Personal weapons
UNIQUEWPNS
Ranged weapons
GUNSMOKE!
Plastic graphics
Enter the character selection screen, select "Load" then enter "FANPLASTIC" as a name. Enter the event selection screen and highlight "Smack Attack". Press Down and select the "Event Settings" button. Then, select the "Options" button and select the "Rendering Modes" button. Change this option to "Render: Plastic". The message "Current mode: plastic" will appear. Return to the even selection screen, then proceed to select a level and begin game play. To return to normal, repeat the steps and choose the cartoon renderer at the "Rendering Modes" screen.
T. Wrecks and Jungle world
Enter the character selection screen, select "Load" then enter "TWRECKSPAD" as a name to unlock T. Wrecks and Jungle world. Alternately, win Smack Attack, Gate Relay, and Flag Relay in all three levels of the Jungle world.
Various Achievements
Complete the following achievements to unlock Microsoft Gamerscore points.
Achievement
How to unlock
Be The Boss (80 points)
Earn a first place finish in each Desert level in Smack Attack, Gate Relay and Flag Rally modes.
Collector (80 points)
Win all levels in Flag Rally mode.
Dodgy (40 points)
Complete 10 sideways dodges in one match by using the right stick or LB/RB.
Drifter (40 points)
Earn double smacks by damaging an opponent in Smack Attack while powersliding with the brake.
Finale (80 points)
Win 12 different matches with a single character.
Flipping Out (40 points)
Earn 10 boosts in one match by completing forward flips with the right stick.
Hoarder (40 points)
Win Flag Rally with at least two captures of 3 or more flags at a time.
New Talent (40 points)
Win any level.
Nitro (40 points)
Win Gate Relay having used turbo boost 20 times.
No Favorites (40 points)
Win Smack Attack while getting points from at least 10 different weapons.
Purist (40 points)
Win Smack Attack while using only your character's favorite weapon collected from "!" powerups.
Smacker (80 points)
Win all levels in Smack Attack mode.
Smart Coyote (40 points)
In Death Valley, drop the 100 ton weight on opponent by shooting the target with your Basic Attack.
Speedster (80 points)
Win all levels in Gate Relay mode.
Steamroller (40 points)
Flatten 3 different opponents in one Gate Relay race by dodging into them with the RS or LB/RB.
Toon Star (200 points)
Win all levels in all modes.
Whack Angus and Desert world
Enter the character selection screen, select "Load" then enter "WHACKLAND" as a name to unlock Whack Angus and Desert world. Alternately, unlock all modes (Smack Attack, Flag Rally, Gate Relay), then win all three levels in the Desert world in each one (total of nine).
