This was a very challenging game, which made it all the more satisfying when I managed to get past a particularly difficult section! I wasn't able to get past the first level, unfortunately, but I still had a good time with what I did play. I'd suggest adding a checkpoint here and there, especially in the first level, just to make it a bit easier in the beginning, but that's personal preference more than anything else. I would also suggest adding some background music, as well, as it being only sound effects left the game feeling quiet (outside of the sound of me dying repeatedly, that is, haha).
Nice work!