Very cute game! Both art and concept.
The only thing I'd suggest is make controls smoother - the movement is a bit too sharp, I think. Maybe use acceleration, or if you are using tweens - make it not linera but sine, etc.
Also, when you activate fire for the first time - the game freezes for about a minute. I think that's the common issue with Godot particles, which I heard is getting fixed in the new version. There is some workaround about it though - like instantiate it while you are loading the game, so it won't take time during the game, or something like that.
Also cudos for godot!