A bit rough around the edges that could do with further refinement but what's here is a decent basis.
The for graphics are a simple yet clean monochrome style which works for the overall game and helps give it a bit of charm.
All the core upgrades are there, double jump, wall climb and dash. I'd just recommend easing off on the gravity a little as the high fall speed makes it feel a bit clunky to make some of the more precise jumps.
The enemy possessing is also an interesting idea with a lot of potential, though it could do with more feedback on how you take enemies over. I think you press J when next to an enemy but its hard to tell as there's no animation.
So overall, not a bad prototype. Some work here and there and it could certainly become something.