thanks. in short u have 3 abilities u can only remember once at a time (one is pierce a bullet pierce through the 1 enemy), no shoot (u heal but u cant shoot for some time), double shoot (2 bullets) and u use r to use ur ability
I'm the second dev here, basically, the tutorial is below in the comments, you can scroll down to read, in short, use R, ability reset when you use the ability and shot once after that.