Welp... kind of a developer's diary type thing... I finally fixed a problem that had been plaguing me since the beginning, the stage portrait for Fountain of Dreams. I've replaced two stages:
Robot Unicorn Attack with Bob-Omb Battlefield
and Fire Temple with Cool Cool Mountain. I got so frustrated because I ran into the same problem with BobOmb Battlefield's portrait, I couldn't figure out why replacing it froze the game... and I finally got it by indexing the colors down to 6... so it doesn't look perfect, but it's better than the portrait for the wrong level. I then indexed a Fountain of Dreams picture and tried it on Mario Bros... and holy crap it worked. So 2.1 is almost ready for release.