The more levels you go up, the more "musicians" are added to the left side, giving a more full sounding song. Problem is, it still isn't very good. It's got that horrid techno "ump ump ump ump ump" bass to it. I still like the old GB music the best.
What's different from this one and the old GB ones (play mechanics wise) is the ability to hit up, which immediately drops the block, having the option to see the next 6 pieces (which I find a bit too much), and being able to hold pieces for later. Of course, there's quite a few other modes of play as well.