All cities, vehicles and modes in arcade mode: upupdowndown
F to fire gun: starpower
F to fire gun, H to fire rocket: leatherandlace
Set difficulty (0=easiest, 9=hardest): howhardcanitbe[0-9]
Trippy Mode: starlite
Unlimited nitrous: yerbamate
Unlock all modes: theparrot
Unlock all cities: griswold