Wow, really great entry! The puzzles were a lot of fun!
It did feel like it took too long for holding the switch to fully turn it off - I didn't realize that's what I needed to do on the second stage for a loooong time. Having some kind of charging animation when you're standing on it would really help to sell that. But having a difference between permanently turning it on vs. toggling it actually makes for really interesting puzzle design, so kudos on that!
The other frustration was that losing all your lives reset you to the start of the game. Ideally in a puzzle game like this one, you wouldn't even have lives, it just restarts at the beginning of each stage. Otherwise you discourage players from experimentation, which is one of the keys to a nice puzzle game.
Overall, this was really nice! Great work!