Cool entry, I really liked the concept! It's fun to play, especially at the later levels where special tiles are introduced.
I think that the introductions to [?] and [!] tiles should convey their mechanics a bit more clearly. At first, I thought that I would have to guess what's hidden under the [?] pattern step by stepping on tiles until I got it (thankfully that wasn't the case, I just thought my guesses were very lucky until I encountered the tile which converted a pattern step into a [?] tile).
Also, it's nice that some puzzles have multiple solutions :) But still, I don't think I did all of them in the 'intended' way :D For example, I didn't use the pattern-changing tile in Level 11 and found a path that didn't require it.
If you update the game after the jam, I suggest adding some more restrictions, like deactivating the button if you step on the switch again or making tiles that disappear after you step off them. That way, the game will be slightly more challenging while still keeping its non-linear nature.