I like the visuals and the 2 characters. The AI seems lackluster as it reacts so fast to your movement that you can't use movement as a strategy also you can just outpace the AI's attack rate. 

This would be a really good opportunity to add multiplayer though. I could see this be fun as a 2 player death match game. If you were thinking of expanding this, I would highly suggest adding multiplayer and more characters.