WonderBoy is a lot of fun. The visuals work well, it fits the theme amazingly, and it is certainly one of the more interesting implementations of said theme. It's fun to play in short bursts especially with the satisfying sound design.

The game loop is quite simple, unfortunately without visual aid on deaths or any sort of score / objective that I noticed it quickly got repetitive. 

It can not be understated how well the visuals here work. They are outstanding. The themes implementation creates situations which turn what I would consider an action game into one where you need to out think your opponent with, at times, you only getting glimpses of your enemy.

Overall it was quite fun, though it isn't something I can play for very long before it feels repetitive. Good job, keep it up!