iOS cheat codes
For iOS versions of the game before version 1.4, you can use the keyboard at the title screen. Since the 1.4 update, that feature has been disabled on all but jailbroken phones and the iPad Touch. "samhines86" unlocks permanent invincibility and "rxh7nigh" unlocks the characters.
During the tutorial (turn tutorial to on in options), quickly swipe multiple times during a turn and the camera will flip around and you'll be on an infinite straightaway with no turns or obstacles. You score will continue to go up and you can collect coins through the Mega Coin powerup, but you can't keep either because the tutorial starts over if you kill yourself by running into the wall.