It took me a while to figure out how the core mechanics worked, but once I did, I found it quite intriguing. I agree with several of the other comments that a better tutorial would really help this game. The first time I solved the first level, I had no idea what I did to solve it and I was completely stumped on the second. I looked at the tool guide, which helped a little, but it was still a bit confusing. I decided to restart, having read the tool guide, and something clicked. The second time I solved the first level, I felt like I had actually solved it instead of just clicking randomly and hoping for the best. The second level still took me a bit, and involved rereading the tool guide, before I was able to figure it out. Once I figured out the first two level, the other puzzles felt far more intuitive. There were still several times I had to really stop and think, but the solutions all made sense once I got there. I think the tool that I had the most difficulties with was the Crescent, but I did eventually get the hang of it.
I wish there had been a way to restart a level. I felt like I made a mistake on one of the later levels, and would have liked to start it over to look at it from the beginning. It's possible I still could have solved it as it was, being able to restart the level would have been nice.
On the final puzzle, I was able to walk through the door before it opened, and fell into the void. I had to return to menu and start over from level one. I was enjoying the game enough though, that I was willing to restart and try again to see if I could complete it.
The art was lovely. I particularly liked the moon phases, and how they looked in both dark and light. The dungeon itself had a good feel to it and it really fit the moon theme of the puzzles.
The game is a good length for a jam game. That said, I reached the end and found myself wishing there were a few more puzzles to do. I definitely think this could be made into a longer game, if you wanted to continue working on it.