invincibility - pause the game then press - l,l,l,r,r,r,r,r,l,l,r,r,l,l.
extra life - pause the game and press - l,l,r,r,l,r,l,l,l,l,r,l,l,r,r,l,l.
extra ray gun ammo pause the game then press - l,r,r,r,l,l,r,r,l,l,l,l,r,l,l,r.
faster movement - pause the game then press - l,r,r,r,r,l,r,l,r,r,l,l,r,r.
less damage - pause the game then press - l,r,r,r,r,l,l,l,r,l,l,l,l,r.
higher jumps - pause the game then press - l,l,r,r,r,r,r,r,l,l,r,r,l,l,l,r.
faster opponents - pause the game then press - l,r,r,r,r,r,l,l,l,l,r,r,r,r,l,l.
slower opponents - pause the game then press - l,l,r,r,r,l,r,r,r,l,l,r,r,l,l,r.
stronger opponents - pause the game them press - l,l,r,r,r,r,lr,r,r,l,l,l,l,l,l.
stronger dexter - pause the game then press - l,l,r,r,r,l,l,r,l,l,r,r,l,r,l,r.it will make dexter destroy robots more easy but it doesn't last for ever.
reverse controls - pause the game them press - l,r,r,r,r,r,r,l,r,l,l,r,r,l,l,l.