first of all THANK YOU! - for binding jump and attack on mouse buttons, such a small thing and almost noone does it. One notion though, i think jump on right button and attack on left would work better.
Game aesthetics felt well put together but levels themselves were imbalanced, trough all 3 levels there was only 2 places where i had to stop and kill enemies, ran trough them very fast - well placed enemies that block the way would solve that. Controls were quite clunky. Skeletons felt and looked like after a while they would ressurect (just gamer gut) and when they didn't it felt off (almost dissapointing) for me. There's a fine line between hard boss and frustrating boss and this one was definitely the latter - didn't enjoyed bossfight at all.
All in all game felt like more or less well put together even if it felt rubberbanded here and there at times - good job with that.