Sorry for the late response, I wanted to get the teams input on this issue ; as our artist was a big fan of your game.
As to the collision I will be going through and changing some of the boxes your comment also led me to find during my exploration into the issue that there are other hit boxes which are not registering correctly. Thank you for bringing this to our attention.
The Artist has suggested adding both a health bar to the player as well as enemies and a tween + sound for proper feedback on hits... Hopefully those will help with this part.