Game ran perfectly here (Firefox, Linux), game was pretty good. At first I had some trouble getting the hang of it but after a few loops I understood it way better. One of the issues I had was that I got a challenge to spend an SP to upgrade a skill or passive, but I didn't know how to get one (maybe I'm just stupid..). Maybe this could be made a bit clearer? Overall it was fun to play, and the higher levels were challenging enough. Good job!