This is pretty good for a jam game. However, as others have mentioned, the controls don't feel good, and I'd also say that the level designs don't work very well for this type of game - there's a lot of jumping blindly over a gap and possibly landing in spikes. Most platformers with limited visibility I've seen tend more towards maze-like levels, which I think works better - there are spikes and hidden pits as well, but the bulk of the challenge comes from trying to find a way to the goal, not from "Oops, you died because there were spikes you couldn't see."