I must say it is a very fun game. I beat level 7 after many tries. This game is in my opinion a lot better than Drawn Down Abyss, which is a bit funny since this is the free game of those two games. One could say less is more.
I must ask, may I fork this game? Looking through the license it looks that the code is "open source" but the assets are not, I can just make my own assets? correct me if I am wrong. One could argue whether the game concept in its self is open source since the game logic is in the source.