This TAS beats the game as Big Mario instead of Small Mario thanks to a ROM hack created by AP. Because of that, entertainment was changed, but optimization hasn't.
This was originally going to be a 21-frame improvement over HappyLee's run due to a faster clip in World 1-2, but I lost that time back from bad Bullet Bill manipulation in World 8-2. Hopefully, that issue will be resolved when I (or any professional SMB1 TAS'ers) get to the run.
This run also syncs with the separate Extra Version (download here), which allows Big Mario's full body to be displayed on pre-level screens and changes the mushrooms into hearts. If you'd like, however, you can download the original patch here.