Graphically the game looks right, but I have some invisible platform and some hole in walls here and there (example:http://imgur.com/Jg5iUHK). I'm not sure what part of my emu is wrong on this. Could this be a cpu bug?
Yep. except some timing issue that I'm currently trying to fix.
Hmm... perhaps PPU mirroring is incorrect?
I doubt it since if that's the case, EVERYTHING would be wrong. But it's only every so often here and there. It's quite puzzling 
yanos wrote:
I doubt it since if that's the case, EVERYTHING would be wrong. But it's only every so often here and there. It's quite puzzling
It looks like the status bar at the top is cutoff. Does the status bar look correct normally except when this happens?
Double check the RAM implementation, that everything is mirrored correctly, and that addresses are correct.
I'm unsure about the "platform", but there's something wrong with your sprite 0 hit detection code.
Yeah, my sprite 0 hit detection is not is bogus, it's just not the priority right now. I'll check my ram implementation and mirroring code in the PPU.