Ring Lab is cool! Nice take on the on\off theme, some fun puzzles, and really great pixel art. It would have been nice to have some music/audio, but I understand the time limitations.
On the final level I went through the door before collecting the white item at the top and the game froze. But it was nice that you implemented a "restart level" function, which I used. And also, an invincibility mode, very nice! So, I did beat the game.
If you get a chance to check out my game Foxy Boom Boxy, I would love any feedback, thanks!