8. Blair Witch
Blair Witch is entirely centred around messing with the player's own perception of reality. Like the movie series it's based on, once you step into the Burkittsville woods, all logic is thrown out the window, as time and space begins to become meaningless.
However, the game also transfers this subversive approach over to the gameplay mechanics as well as the presentation, which ties into the ending.
Throughout the title you're facing off against a psychopath called Carver, who's being manipulated by the titular witch. As is Blair Witch tradition, on your journey you come across plenty of creepy idols scattered around the woods which scare your dog, Bullet.
The game lets you destroy them, and it's hinted that this is somehow hurting the monster hunting you. However, the final twist reveals that destroying these totems has actually given her a deeper influence over your actions, and with each one you've become more susceptible to her manipulation.
By destroying a bunch of these you'll net the bad ending, which sees you killing Carver and taking his place, a new puppet of the Blair Witch destined to kill anyone unlucky enough to find themselves lost in the woods.