I've got issues with the sound effects ingame. They keep getting mixed up. Sometimes the brick delete noise changes to some sort of whoosh, and I get bangs when I move the ghostbrick. Sometimes menu sounds get switched with the death noise or other things. All in all, I think the gui needs bug-checking, as all of these problems are minor, but annoying.
Also, the game gets crappier and crappier the more times I start a game (mission). It goes away when I shut it off and restart it, but that could be problematic in the future.