Really excellent work, super polished! Seriously amazing that this was made in such a short time frame.
I don't like the timer feature, or end level scoring in general, they're a turn off to me as they feel like artificial noisy content. This is just a personal complaint about casual puzzle game design in general, I know many people are fond of these kinds of features. Lastly, an undo option is IMO a bare minimum quality of life feature for these kinds of games, hopefully you'll add one in an update.
I appreciate the in-game logic/justification for the restart system, that's a nice touch!
Re: end level scoring, the coins could be an interesting idea if collecting them was a noticeably harder/different solution than just getting to the end without them. However, it always felt like they were on the main path and no harder to collect than it was to finish the level, so i don't get the design choice.
Anyway, again - really awesome work, and some solid puzzles. :)