Don't mention the goddamn pit in Robot Factory 3! Argh!! It took me so much time to figure it out!!!
Oh yeah, and thanks for helping me at Final Factory, I'm gonna try it right away.
EDIT: Okay, I tried it out and completed your hack. MASKING A LEDGE AS A WALL BY USING BACKGROUND IS EVIL. PERIOD! :D
1) You've got it perfect with the increased boss hit-counts. Metal Sonic is now actually hard. (since 6 of the 8 hits could be done in an "automatic" way, increased hitcounts now get a good length -- he is now pretty tough to defeat, since you need to destroy him before he does his spike-jump, which is pretty much an unavoidable death)
2) The final boss is now a bit easy with the ledge at the top: the trick of holding a spindash in place to damage a boss still works.
3) Love the boss music.
4) Boardwalk boss is still as bastard as ever. ;)