I think there's a decent core of a game here: movement feels pretty good (sometimes the jump can act a little funky), graphics are bright and explosive, and the shooting is nice. I feel like it just needs some extra touches to make it really stand out as it feels really dead and dull to me after just a few levels. While there is a nice variety of enemies in the end, the levels are very samey and don't change, the soundscape is very empty leading to a hollow feeling, and there is no significant story or progression in place to drive you forward. With those in place, I feel like this could be really great.