The art and music are incredible. I like the simplicity of the design, yet there's still room to add more if you ever feel like revisiting.
Am I correct that it's only 1 battle? I wasn't quite sure if it was sort of a "go for as long as you can" type situation, then I suddenly won and couldn't click continue, so I'm assuming it's just sort of a "demo-battle"?
Regardless, awesome job!