This patch adds a stage select, power-up and framerule selection to SMB Special.
Get the latest version at https://github.com/threecreepio/smb1-practiserom-smbspecial
The easiest way to apply this patch is to go to https://www.romhacking.net/patch/
Place the Super Mario Bros 1 rom in the "rom file", and the IPS from this archive into the "patch file" and press apply patch!
You can of course use Lunar IPS or FLIPS if you'd prefer.
/threecreepio