Inspired by Pellsson! https://github.com/pellsson/smb
This patch adds a stage select, power-up and framerule selection to SMB1 Romhacks (or the original game if so desired.)
For now this only really works well on fairly basic romhacks that don't alter too much of the game code.
The easiest way to patch a romhack is to visit https://3.creep.io/smb1/practiserom, drop your romhack rom into the file select.
If it applies cleanly you can download the resulting file from the page!