This is a great product. Really nice, it look good, it sounds good, it feels good. Had a lot of fun, although I got only a final score of 3100 with successfull leaving the cave.
I observed some little aspects, if you allow me to share them with you.
First: It is sad, that I can not swing while I'm in the air. That takes away some interesting possibilities for gameplay. Second: When I lose, the Restart Button doesn't work for me. It only does, when I successfully leave the cave. Third: I loved the first minute of the soundtrack. But the second minute, where the synth comes in, was heavily unexpected and partially broke the game feel for me. I would recommend to try out Mallet Instruments, as they sound a bit like shiny gems look like. Using them in combination with a slightly tempo up over the course of the second minute could also have a nice effect.
But these are only meant as cherry on top suggestions because the game that I just played was really awesome and packed with super stable mechanics and a lot of fun to play.