This was done really well and it feels good to play. It seems like you put a lot of time into designing each enemy and each gem and balancing them accordingly so I feel you should have implemented a menu that tells you exactly what each gem and enemy does or a tooltip where holding shift displays what each does. A lot of time is wasted at the beginning trying to figure out the point of all the different gems because of the lack of knowledge. Great job on this one I had a lot of fun playing it