Not bad...But could use some improvements.
First, the whole one-hit kill thing for your character makes this seriously harder if you don't kill the oncoming enemies fast enough. Second, not being able to dodge the boss makes this very difficult. All it takes is one touch and he kills you. Maybe if there were some powerups for the gun or maybe some kind of armor/defense for Blot, getting past the first boss would be something that is achievable.