Honestly, is a pretty solid foundation, loved the graphics(Especially the sword) and loved the music. The main problem with the game its that after playing a couple of minutes, i reached level 11 and started to get tired of just running and srpingting, not really fighting the enemies. I suggest to add obstacles so you actually use the moving mechanics such as jumping and sliding.
The maze generation its awesome and i loved the black hole animation, and it follows the theme correctly. Keep it up man!!!