Hey! This was a lot of fun! It barely took me a moment to figure out how to play!
I will say one thing though, it wasn't immediately obvious that SPACE was the enter button.
I would change it to ENTER, but you could also set up multiple buttons to work too. I'd recommend; Z, ENTER, SPACE, Right arrow.
I'd also set up some more buttons for exiting menu's too. ESC is fine, but I'd have the options be; X, BACKSPACE, ESC, Left arrow.
The reason why I've included the arrows is because the arrows are used to pick an option in the menus. Although they probably wouldn't work very well in the character select unless you make it vertical instead of horizontal, but it'd probably be better to just ignore using the arrow keys for the moment.
Hopefully this helps!