I really like the idea and level design, but the glitchy physics and lack of checkpoints make it frustrating. Spacebar as reset may not be the best choice, either, as it's easy to press on accident. Edit: okay, yeah, I've accidentally pressed space twice now and fell in lava once and I'm going to have to take a break because that's so annoying and it's not fun to have to grind through the beginning again.
The buttons and switches could use more feedback to let you know when they've been depressed/flipped, and to show what they did. The first two, especially, since they require backtracking after being used and that feels unintuitive at first.
Overall, fun but buggy/glitchy!