Nice game design right there, gems are really well executed(even if there is no reason to get them hahaha) but it is a nice touch on the final game! Audio is really good too, puzzles are hard(I'm okay with this, maybe others won't) and really makes you be careful when rewinding. In my opinion is no hidden gem or anything perfect, but it is a nice idea, with nice execution and I liked it! Congrats!
Be sure to check my game too!