Looks interesting so far! I think these mechanics are really neat, and can lead to some deep puzzles. Some thoughts on the sets:
A: I got stuck on level 4 here. I think the idea that it communicates probably could've been done better with either a smaller setup, or more reinforcement of the general idea beforehand.
B: Level 2 might not be the best way to teach that concept? It seems like a weird way to introduce it.
C: The crown symbol tutorial was a bit too easy to misinterpret, because the only real 'communication' of the concept seems to be in the first level. I'd recommend adding some more tutorial levels that more directly hint at the concept. (For instance, in the first one, it might be good to put the crown on one side rather than in the center.) Also, it seems that there's an extra condition on crowns that doesn't appear anywhere in the introductory levels here? In D7, this solution doesn't work, and I'm not sure why: https://cdn.discordapp.com/attachments/526649761105969153/746561581290094682/f892d376be.png
D: This mechanic is pretty simple by itself, but the way it combines with others is cool. Love how it introduces an asymmetry - puzzles 4 and 5 show that off nicely.
Oh, and it would be nice to have solved puzzles marked, and have a way to go to the next/previous puzzle without having to go back to the list again.
The game asked me to send screenshots of some solutions, so:
B5: https://cdn.discordapp.com/attachments/526649761105969153/746557126066831420/b1430576f9.png
C8: https://cdn.discordapp.com/attachments/526649761105969153/746560047848620112/ae5366de68.png
D7: https://cdn.discordapp.com/attachments/526649761105969153/746559447052058645/45837d8758.png
