Start game as usual, during gameplay go to the Secret codes menu and use the following codes:
Unlock - Unlock All Missions (MasterCheat)
GazerBeam- Shoot Beams For A While
SmartBomb- Kill Enemies And Every Item Near You
SassMode - Game Becomes Faster
UUDDLRLRBAS- Refill 25% Health
Showtime - Get Incredipower For A while
DanielTheFlash - Get Incredipower For Superspeed - Press
Right Mousebutton While Running
McTravis - Get Incredipower - Press Right Mousebutton
For Fast Running And Ramming Everything
Kronos - Get Windtrails And Superpunch
AthletesFoot - Enable Fire Trail
BWTheMovie - Toggle Player Slowmotion
InvertCameraX- X Cam Controls Change (Mouse)
InvertCameraY- Y Cam Controls Change (Mouse)
Einsteinium- Large Head
DeEvolve - Small Head
bHUD - Toggle Hud
BoaPlace - Nothing
RotAIDalg- Nothing
Hi - Show Intro
YourNameInLights - Show Credits
TheDudeAbides- ?
SpringBreak- ?
PinkSlip - ?
Labombe- ?
InvertTurret - ?
EMode- ?
DiscoRules - ?
Dandruff - ?
TonyLoaf - ?
Flexible - ?
DashLikes- ?
Notice that some codes only work on certain levels/missions.
To enable MasterCheats you must first add "AllowMasterCheats = 1" (without the quotes) on a separate line to your .Gamein.ini file then restart game. The way to know that AllowMasterCheats has been correctly activated is by looking for debug info during gameplay, namely game build version aswell as a FPS counter will show on screen.