It's a fun game, great soundtrack, but two major flaws.
#1. There's a lack of diversity in the levels. After awhile, you're just doing slight variations of the same thing over and over. To be fair, the game has a kind of permanent beta feel to it.
#2. That in itself wouldn't be the end of the world, since it's a pretty fun game. The biggest problem is that a few times since I've bought the game, the developers have just erased all of my progress when they've introduced what they see as a significant change or upgrade.
I might start playing it again once the game no longer feels like it's going to just evaporate and restart on me without my consent.