In Outlast, the player assumes the role of freelance investigative journalist Miles Upshur, as he navigates in Mount Massive Asylum, a dilapidated psychiatric hospital in the mountains of Lake County, Colorado, that is overrun by homicidal patients.

Documents can be collected, which offer backstory and other expository information about the facility, including pages taken from patients' diaries and reports from the hospital's staff.

[8] Developer Red Barrels have pointed to the survival-focused gameplay in Amnesia: The Dark Descent (2010) as a primary influence on the combat-free narrative style of Outlast.

[10] Freelance investigative journalist Miles Upshur receives an anonymous e-mail about inhumane experiments at Mount Massive Asylum, a remote psychiatric hospital owned by the notoriously unethical Murkoff Corporation.

He is informed by a dying officer of Murkoff's private military unit that the hospital's deranged inmates, known as "variants", have escaped and are freely roaming the grounds.

He also shows Miles footage of the "Walrider", a ghost-like entity that kills patients and staff alike, which he claims is responsible for the hospital's dilapidated state.

He escapes through the sewers to the main wards, pursued by Walker and two cannibalistic twins, only to be captured by Richard Trager, a former Murkoff executive driven insane.

Miles reaches an auditorium and learns that the Walrider was created by Rudolf Wernicke, a German scientist brought to the United States during Operation Paperclip.

Wernicke believed that intensive dream therapy conducted on traumatized patients could connect swarms of nanites into a single malevolent being.

In the chapel, Miles finds a crucified Father Martin, who gives him a key to the lobby elevator that he insists will take him to freedom before immolating himself.

Miles locates an aged Wernicke, who confirms that the Walrider is a biotechnological nanite entity controlled by Billy Hope, a comatose patient of Murkoff's experiments.

While a horrified Wernicke realizes that Miles has become the Walrider's new host, panicked screams, gunfire, and mauling sounds are heard as the screen fades to black.

[2] It serves as an overlapping prequel to the original game, showing the events both before and after the main plotline, and follows Waylon Park, the anonymous tipster to Miles Upshur.

After witnessing the engine's effects on the abused patients, a horrified Waylon sends an anonymous e-mail to Miles Upshur to expose Murkoff's inhumane experiments.

Gluskin tries to hang Waylon in the hospital's gymnasium with his other victims, but during the struggle, he is entangled by his pulley system and a sudden weight shift causes him to be fatally impaled on a loose section of rebar.

"[27] Marty Sliva of IGN rated the game with a score of 7.8, praising the horror elements and gameplay while criticizing the environments and character modeling.

And as a reporter, you don't possess many skills with which you can fend off the hulking brutes, knife-wielding stalkers, and other homicidal maniacs who lurk in the halls of the dilapidated Mount Massive Asylum.

On March 6, 2017, Red Barrels announced that a physical bundle, Outlast Trinity, would be released for Xbox One and PlayStation 4 on April 25.

On October 30, 2024, it was announced that a film adaptation was in development at Lionsgate, with Roy Lee producing and J. T. Petty, who wrote the original game, penning the screenplay.