Pretty fun game!
Most of the levels were relatively easy but the game obviously gets exponentially harder with fewer colors. It reminds me a lot of Simon Tatham's 'Mosaic' puzzle, except with actual pictures. I'm guessing the puzzles are being generated entirely based on the solution image, but maybe a greater challenge could be created by manually selecting some information to remove? 24 was my favourite level because the eye colors that you usually do first ended up being the last thing which I thought was neat. My only complaint is sometimes it's hard to distinguish color indicators, like level 11 where a black color indicator can look like dark blue when the background is light blue, though it's more so a drawback of Pico-8 .
Kind of a complex puzzle concept but I think you implemented it perfectly!
Thanks @OrbWinder! I'm glad you enjoyed the game and really appreciate your helpful comment. You're right about puzzles being solely generated from images, though I always check they are solvable with pure logic. I guess you're already familiar with this kind of puzzles, looks like Cluepix is of an acquired taste as either people already knew Picross, Nurikabe & alikes and enjoyed my game, or they just didn't understand it. But the game sure isn't flawless. I'm working on a version with new and more progressive puzzles that'll be out in december. A simpler version too as I'm not 100% happy with the colors stacks right now. It makes the game and UI rather busy and look more complex than it is. Some colors being too close, as you saw, is also a problem that version should fix, having no stacks or even palette.