I was looking for easy to play / hard to win mind breaking game and finally found it. Ebobo: The hardest puzzle game. I can prove that it's insanely hard puzzle with very intuitive rules. You have to just tap on tiles and they will flip as cards. Tiles have two colours on both sides, and the goal is to turn the grid into one single colour. Challenging here is that how tiles are changing their colour: whole row and column affected at once in turn.

The game concept is great, but lack of visual effects (style at all) makes this game very niche and "too indie". Hope developers will see my review and improve the game!