I might have been able to do this with NSMB for the DS if I practiced a bit for it. I knew I could play without stopping during the last level and it's just memorizing the buttons that were pressed to complete the level. I can't really talk about the boss fight tho since I can't really remember how it goes ;~;
It's impressive, but I'm more surprised that people can beat games like the Legend of Zelda Ocarina of Time blindfolded. Seems far more complex to figure out and memorise: