Great game. Smooth music (lets you play it for a long time without going insane) and great colors. The only thing I missed was a button in the options disabling the scrolling appearance of the text. Like "make level descriptions instant".
I don't really care that you have to pay for some content, most games are that way these days. However, I will have to rate it from a broke players perspective, and since the free part of the game is really really really short, it scores just a 2/5, like pretty much any game that short.
I like the idea and everything, but the fact that you need to be sooo accurate in your jumps to continie made me stop playing after just a few minutes. That totally destroyed the game for me. 2/5