The art is cool, while simple it really fits the atmosphere. I liked the warped screen, reminded me of good ol' screens, it was a nice detail. An undertale-like music would have made it incredible. I was honestly amazed by how good the controls reply, it's just too bad that there was no tutorial screen at all in game to tell you what keys to use, and you have to read the game description instead.
I kind of suck at platformers though, so I was stucked in the room with the kind of big eyes that shoot projectiles at you. While it's great that there is a checkpoint here (I could try multiple times), I found it quite unfair that the projectiles go through the plateforms, cuz the only time I managed to not land on the spikes I got killed by a projectile from under the plateform.
Though, I had quite fun exploring the cave and testing stuff, and my awful level at plateformers is not a real criteria :D great job :3