Known simply as P.T. at the time of its release on the PlayStation Store, this free playable teaser for (the eventually canceled) Silent Hills game was an interesting and unique psychological survival horror.
As the mystery protagonist, you find yourself in a corridor which you must explore (and which you soon realize is endless, as you are caught in some kind of never-ending loop).
The key is to work your way through the game until the moment a phone starts to ring. Once this has been triggered, you are released from the hallway and are rewarded with the trailer for Silent Hills.
The objective isn't as simple as it sounds. You have no combat skills, and must investigate various frightening situations and solve challenging puzzles. The corridor will continue to change around you each time you complete a loop of it, and this can go on for hours, adding to the desperation you already feel.
One scary aspect of P.T. that keeps you on your toes is the hostile spirit Lisa, whom you encounter numerous times throughout the game. However, it's the moment she attacks you suddenly if you let her get too close that really takes you by surprise, and provides one of the most terrifying jump scares on this list.