The Stanley Parable is an interactive fiction modification built on the Source game engine, developed by Davey Wreden and released in July 2011. A high-definition remastered version, including new story elements, has been approved for the Steam Greenlight process, and it will be released in October 2013.
While the modification uses the first-person perspective common to other Source engine mods, there are no combat or other action-based sequences. Instead, the player controls the protagonist, Stanley, through a surreal environment, with each step of the process narrated. The player has the opportunity to make numerous decisions on which paths to take, including going against what the narration is telling them to do, with each choice leading to different narrations and endings.
Wreden envisioned the game after considering that most major video game titles confine the user to its rules, and considered how to construct a narrative to challenge that notion. Outside of Kevan Brighting's voice work of the narrator, Wreden built the modification himself, initially as a personal project for his career goals but soon expanding to a wider release once he had shown it to friends and other players. The modification received critical attention as a new variation of creating interactive fiction within a game engine, and provided a thought-invoking narration to discuss with others on the nature of choice and predestination within video games.
I seen the demo on Steam and downloaded it. It's pretty funny, kinda like portal humor.