Using Snes9X 1.43-dev. Abused a programming error in Donut Plains 1 to finish quicker. I took multiple hits in Yoshii Island 3 and Bowsers Castle to go faster. Aimed for fastest run with as few re-records as possible. Did not use any slowdown, the game was played at full (60fps) speed.

The hardest part was probably the ghost house. You might like my version over the current world record because I put on a bit of a show :)

Bisqwit: Can you explain what are DP1, YI3 and BC?
Oh, and also since this movie fails to beat the existing record, despite competing in the same category, I'll reject this submission.
You should note that we're not having a skill competition here, thus "played at 100% speed" or "least rerecords" don't have value to us, quite the contrary.