I was unable to figure out level 4, unfortunately. This was really great though! I've seen a lot of games where one controls multiple characters, but this is unique among them I think. Simple yet effective. I had a bit of a panic because I thought maybe the areas without walls (along the edges) were some sort of pit to avoid, but that wasn't the case. Music didn't seem to loop after a while...not sure if it has a delay or just wouldn't. Great job overall!