Nice entry. It's a cool concept and a solid prototype for this sort of game. Some additional feedback would be helpful - it's unclear what some of the upgrades do, and a visual cooldown of the fireball would be appreciated. The blood effect is pretty satisfying. There's a lot you could add on to this type of game to really make it something special - a loss condition, a bit of music, maybe some more enemy types and a progression system. Good job!