I came to the Media Thread specifically to recommend Undertale.

I worry some that casting it as "a game where you can be pacifist" spoils some of the experience. The game tree is apparently very dense, with many gradations of behavior, but the poles (of genocide and full pacifism) are obvious attractors. And I still enjoyed it immensely, only playing full pacifism, so maybe I shouldn't worry that someone else is jumping straight to the good stuff instead of discovering that the good stuff exists after toying around with it.