The game is nice and creative, I would add more sound effects (at least for the shooting - the most important), and improve the UI a bit.
I would keep the art style because it really fits the game.
But there are things that I still don't understand about the game - Is the white obstacle a mineral? if yes why is it damages me? and sometimes it doesn't damage me, why I can't shoot enemies (the green animals) and etc.
Overall good job!