It would be nice if CPU could control player 2, I don't have friend :P
Some interesting ideas here, but it's all kinda random. The characters don't match the environment, nor do the buttons. There needs to be a way for the game to end or at least complete a "cycle." Such as, pressing all buttons causes a new weapon to spawn, and a wave of monsters.
Also, the jump is a bit crazy. It feels weird to move so quickly up and down but much slower side to side. Might be better with less power but also less gravity, allowing you to float more.