I like the artstyle of the game which you created yourself. It looks hand drawn but i'm not sure, it could be pixel art as well. Although it doesn't really appeal to me, i like a cleaner looking art. This was too expressionist for my taste :) Speaking of expressionism, i think you draw some inspirations from Blasphemous. I get that vibe from art, animations and music also the overall vibe of the game but i might be wrong. Also the grafting mechanic i think is taken from Elden Ring which almost works the same way as this game. I love seeing references from other games in jam games i play.
The boss designs look visually good. Especially the first one but their attacks were too predictable. They give too much window to attack, they stay idle too much which makes them easy. I think 2nd boss has phase 2 but i'm not sure. 1st and 3rd one i don't think they have it
Controls are standart 2D platformer, they work fine but turning left and right is not very responsive, not very snappy if you will but it's no big deal.
Grafting mechanic is very very cool. I gave 5/5 on that one bcs it definitely deserved it. You gain a different attack and you can see the limb you exchanged on your character. I totally dig that!
Overall it's a very solid game. The 2D art and gameplay mechanics need some improvement i think but it's still good game in it's current state. Great job for your team and best of luck!