Cool prototype, I probably have already said this in a thread but the visuals are amazing and look highly professional. I'm not someone who plays this kind of game consistently but I did find it fun.
One thing that took me somewhat long to figure out was how to break bubble in the last room (I don't think I saw a tooltip for that?). But I guess its the point of being the end of the demo.
Also dunno if its a bug but when low on health and you loose something like a foot it keeps moving the bullets? If its intended thats cool.