This is really fun and I can see it doing well commercially! The only thing that bothers me is having to keep the mouse clicked. I know there is an upgrade to invert the controls, but imo it should not be that way, it should be the default setting
Agreed indeed, it feels kinda lame to have to buy an upgrade for that, which is possible quite early in the game. Also, I tend to avoid the purple triangles instead of using the (inverted) click to turn off my fire, so it's not really useful.