Enter the following codes at the ‘Cheats’ screen:

citybeaconsWin everything
inflatedegoBig head mode
iwishUnlimited time   
tearoundAlways win
travoltaPower-up moves   

Extra boards:

Combat BoardBeat the boss on the UK course 
Speed BoardBeat the boss on the US course 
Trick boardBeat the Japan course  

Thanks to Revolution readers Gman10, Brian Milan, Homey G., K-Rock, and zombieman_3000!