Hi there! Sorry for the late reply. And thank you, I'm glad you like the game! It was my first game of this kind, so the sound wasn't the priority, but when making another in the future, I'll try to include some fitting audio :)
Regarding your questions about the puzzles, allow me to give you some hints. If that is not enough, just ask. (I've added some formatting to avoid spoilers for people who wouldn't want it.)
=========== SPOILERS ===========
1. The "..." = "..." x "..." puzzle - It's a sort of a 'multiplication', but not the arithmetic one (if you look up what operations it can represents, you'll find a set of those, and the correct one can set you on the right course ;-) ). You need to figure out what shapes are needed on both sides of the x to produce the required shape.
2. The puzzle outside - those are actually hints. And two separate ones. My bad I didn't spread them apart enough.
- The left one just explains
what locks you out of the stone and completing the game. - The right one... well, that one is optional.
It's a way to circumvent a part of the final challenge.It's a bit over the top, but it's meant to be like that. That one I don't want to spoil and it's perfectly fine for people not getting it the first time. :)