4:53 HAS BEEN ACHIEVED!!! There are a few quirks about this rom hack that make it very unique to run: You need a different setup other than sockfolder FPG in 1-1 to save the framerule, you can go directly in the World 4 pipe without having to load the warpzone, 4-2 needs 376 IGT pipe entry to save the framerule, BBG is more difficult and needs to be done differently due to different enemy bounce heights, 8-3 FPG can be done with 243 IGT because fireworks work the same way it does in SMB2J, and 8-4 needs to be played faster than normal due to extra loading frames between rooms. I would probably compare the difficulty of this time to a 4:55.2xx in SMB1 Any%. Either way, I am very proud of this time!
Played on Original NES w/ EverDrive N8 Pro

Following a few requests, a practice ROM for Super Mario Bros. Definitive has been released, which can be found under the Resources tab. Enjoy!