6.  Corpse Party

Will they ever survive the school of the dead? 

A group of naive school students perform a ritual that sends them into an otherworldy elementary school filled with ghosts. Though the graphics are simple, the eerie gameplay and the soundtrack are awesome. Also, the choices of the players affect the outcome of the story.  Word of advice-do not play game this in an empty classroom or get too attached to the characters.  

Check out the gameplay here: 

Corpse Party Gameplay Video.