Tiny Hexxagon

This game has very and clean basic interface and simple rules. But with dozens of board shapes and several AI difficulty levels it can be easy or difficult to play depending on the settings. It does not have interruptions from ads or "achievement" awards like most games do. This easy to learn game with multple levels of difficulty is great. The only improvements I can think of is the ability to save a game to continue later and a 2 human player option. Otherwise the game is nearly perfect.

2018: Absolutely lovely, cute minimal design, very simple game with interesting boards, would be nice if you could switch the computer for a human. 2025 edit: Multiplayer was added!!

Perfect! It has the simplest graphics, no unnecessary clutter and NO ADS. It's simply beautiful.