Congrats on finishing the jam!
It was a short and sweet story. Even though the art was fairly simple, the animation for crouching or the punch was very smooth. I liked how the colors easily and quickly represented the strength/weaknesses. However, one thing to keep in mind is that people who are colourblind would have difficulty with this aspect. Adding an additional shape or change in silhouette to the and the player would help.
I found it very easy to cheese the game by "kicking" the enemy (i.e. crouch and punch). It seems like the GDD talked about audio, but I didn't hear any - would've been nice to have but probably was cut to reach the deadline. Or a bug.
Otherwise for the story, I had hoped that as you fought each enemy, their blood was on your hands and would change the players own color. Might be an interesting concept to explore. Great job!