My only question is that is there a way to get health back?
Other than that its a good game, challenging to beat for even players like me, who I would consider decent at lots of games out there. Something you should consider is giving the player I frames when in the menu to get upgrades. Upgrades are helpful although some of the enemies are still very hard, the lunging enemy has a bug where it spins like crazy then lunges the entire screen hitting me almost every time, (unless that was intentional), I haven't played long enough to see enemies past wave three I believe.