You really went above and beyond on making this a calming, absorbing experience. It definitely feels like something you'd just mindlessly play on your phone when you need to relax.
I would say that the mechanic seems to be begging for more complexity. You spent all this time making a really cool shader that could be capable of really cool, mind-bending puzzles, but with the current implementation, you can practically get through every level without needing to ever get a different perspective on pairings.
I think if you spend a little time post jam thinking of different ways you could use the shader and playing with prototypes, you could come up with some amazing things that could rival some of the more popular puzzle games on the market.
Either way, you did an excellent job, and this comes across as one of the more complete, polished games that I've seen so far!