You have a README which is great, but you'll need a License file as well (these are two main criteria for open source category). Spice up your README a little with things like emojis or screenshots.

Loving the art-style and graphics. Music is funky and fits well. Controls are slightly annoying, when I walk up to the fire dude to hit him, the character turns around without me pressing any buttons, so I end up dying, and the contact doesn't always work for hitting the enemies. Great concept and good solid base. Well done.

Took me a while to realize you have to keep switching weapons to maintain balance. With that in hand, it’s pretty nice! It might benefit from some more prominent alert when the balance meter is about to kill you.

Fun game, with great visuals, theme was also on point. It's a bit hard I would say and unforgiving, would also loved some visual/audio feedback for when getting hit, nonetheless I had a great time, good job!

I think a quick tutorial or just some text explaining the mechanics would have been super useful! I read the comments and understood that I could and needed to change weapons. Not quite sure how are "swords and bows" related to "demon and angels" (the UI bar that displays the balance has this motives). Great music and great visuals! the game worked correctly and was fun to play. Congrats!

I died couple times and then finally realized that I should switch weapon to keep balance! lol 
The concept is innovative. I think it will be a room to extend the concept. Nice job!

Also, I love the visual and pixel art characters and elements in the game! Well done.

I love the  game idea