Excelent game! I have beated in normal difficulty. I would suggest the boss were a bit harder in this difficulty, though, since previous waves were harder than the boss itself. Game very well polished, with good sounds and visual feedback, combat is really cool, I would suggest kick in Space Bar, instead of E, but I could play normally. The upgrades and the Risk Factor is really cool ideas, I was kicking everyone every hour lol, really fun game, congrats! (5 stars in every category, btw)