I'm not technical, so I don't know much about this sort of thing, but from what I can gather Game Maker can be a pain is the arse. It's good that you're trying though and it seems to be coming along well. I saw a remixed version of SMB3 that someone made in Game Maker, it it was very difficult to tell that it wasn't one of the special levels in the japanese GBA version. If you try hard you can get the physics to work pretty well. I hope that it stays togetehr with whatever you have planned, especially if there's any hot action, which as far as the old Sonic games go, should be okay. There was never anything too much going on, and the worst of it was the airship cutscenes in Sonic 3 & K, or the Death Egg explosion.