Sonic Before the Sequel has a Mac port by Guess Who, if I'm not wrong. You can play through the main game but can't go through boss attack or view the cutscenes. It's good enough though :P
Yeah, we seriously need a full on Mac port for ATS some how. With the whole cutscenes issue, is MMF2 able to take .mov for videos? I know that Macs can play those no problem. If somebody could somehow decompile BTS, I'd be happy to see if I could get .mov versions of the cutscenes. Speaking of cutscenes, I've gone through ATS' cutscene folder and found a few (as of yet) unused cutscenes. Interesting... There's also some unused cutscenes in BTS '12, probably ported from the original game. However, I found a duplicate of '11's bad ending, though the two files have different names... I need to look into this more... I like ellipses...
The hell are you doing with a Mac. Get a PC. Best solution. My deepest condolences go out to you and I wish you an abundant PC future.
I think SRB2 has working Mac versions, although I also believe they're incompatible with Windows versions when it comes to multiplayer.
I have a version of sonic classic 1 for mac. There was really no demand for it, so I quit. It only plays through the game like sonic 1 and is stripped of all extras. Just install a guest windows machine, it's way easier.