Hue is a vibrant, award-winning puzzle-adventure, where you alter the world by changing its background color. Includes full colorblind support, using symbols as a color aid
https://www.epicgames.com/store/en-US/product/hue/home
Next week there should be 3 free games, Killing Floor 2, Lifeless Plant & The Escapist 2.
Oddly enough they've dropped giving Conan for free this week, maybe we'll see it another week like we have for The Escapist 2.
Edit: Seems Conan might not be free in the future either:-
The Epic Games Store team has decided that Conan Exiles will not be free, but will be available for purchase on the store at a later date.
https://twitter.com/EpicGames/status/1278694655744454658?s=19
Edited