Fez, a cross-dimensional 2d platformer made by Phil fish. I really wished he didn't get into so much social media drama/ flame war or make controversial statements on public appearances. Nonetheless, very interesting concept.
One of the scariest survival horror game with a game mechanic that is unique. In this game, you escape a facility after a couple of creatures escape containment. One of them is a statue that you have to maintain eye contact, otherwise it'll zoom towards you and kill you instantly. To make things more fun, your character will blink every few seconds.
Penumbra overture was one of my favorite survival horror games of all time. This game, however, removes horror and focuses on puzzle solving. Nonetheless interesting to solve through.