Really fun once you get the hang of it.
It’s hard to tell at any point if the character’s attacks will hit an object in front of him. A shadow right under the character or something like that would be really useful.
Moving and attacking cancel each other’s animations. Which creates a bit of an unpleasant feeling in my opinion. The optimal way to play is just hold down space the entire time and move around like that.
Scaling the screen, going fullscreen etc. has some unintended effects on the UI. Some elements don’t scale while others do. This can cause some text to be illegible and put things like the Name input field to go off screen.
If the stage layout was randomized each time, and the controls felt a little better, this could be a really addicting game in my opinion.