YOOOHOO!!
dunno if this is posted yet but the mario video is a fake..
not exactly a fake....the guy used an emulator to finish the game which he could save/load whenever he wanted
so basically he saved/loaded about 15,000 times...he played the game at 1/30 speed and recorded it framewise
but theres no cheating like...invulnerability/cheats etc etc
theres a ddiscussion of this at
www.ign.com forums