The game centers on protagonist Sebastian Castellanos as he is pulled through a distorted world full of nightmarish locations and horrid creatures.

Played in a third-person perspective, players battle disfigured nightmare-like enemies, including bosses, using guns and melee weapons, and progress through the levels, avoiding traps, using stealth, and finding collectables.

[5] Players have a safe house called 'Safe Haven' that can be accessed during scripted events and by finding bright glowing mirrors.

[11] While investigating the scene of a mass murder at Beacon Mental Hospital, Krimson City Police Detective Sergeant Sebastian Castellanos, his partner Joseph Oda, police officer Oscar Connelly, and Junior Detective Juli Kidman find themselves suddenly thrown into an unreal world, after hearing a high-pitched noise.

Upon reuniting with his colleagues, they attempt to escape via ambulance while Krimson City is destroyed by a massive earthquake, eventually causing them to crash.

Freeing himself from the wreckage, Sebastian wanders through dark forests and abandoned buildings full of monstrous creatures and witnesses the apparition of a disfigured man in a white hood.

Deeply traumatized over Laura's death, Ruben eventually killed both of his parents, took control of their fortune, and continued to "donate" money to Beacon Mental Hospital in exchange for test subjects for his experiments into the human psyche.

Ruvik began designing STEM as a means for him to reshape reality, so that he could physically travel back into his memories and live his life again with Laura.

In retaliation, Mobius simply killed him and extracted his brain for installation in order to use the machine, thus allowing Ruvik to maintain control of the STEM world.

Kidman realizes that Mobius in fact wants the meek Leslie as a replacement for Ruvik's brain – an easily manipulated 'blank slate' mind, which they can use to power STEM and create a world of their own design.

When Jimenez, aided by Sebastian, tries to use Leslie to return to reality, he realizes that Ruvik wants to transfer his mind to a compatible host, and escape into the real world.

Entering the machine, Kidman is attacked by Oscar Connelly (Kiff VandenHeuvel / Keiji Hirai) while in the forest and falls off a cliff.

Waking up in the Safe Haven and meeting Tatiana Gutierrez (Julie Granata / Yūko Kaida), Kidman explores the area before being able to leave.

Reaching at the terminal, she is led back to Krimson City and goes through the police department, where she sees memories of Sebastian and Joseph and begins feeling sympathy for the former.

Heading back towards Beacon Mental Hospital, she meets up with Sebastian who gets turned into a Haunted by Ruvik but manages to save him and find Leslie.

Following this, a scene from the main game plays, but from Kidman's perspective, as she sees the Administrator instead of Sebastian, who informs that they know what Leslie will become and that Ruvik is a corpse.

Rushing through dozens of Haunted, Kidman is able to get in an elevator that leads up to the apex of Beacon where the Mobius facility is, as the Administrator taunts Kidman, explaining that STEM was built on the premise of fear as a way to control individuals, with the true purpose of her mission serving as a test run for the Administrator's new method of infused control.

Awakening in the real world, Kidman sees Leslie emerge from a STEM terminal and being taken away along with Joseph, as well as the vessel that housed Ruvik's brain now empty, much to her confusion.

[12] Resident Evil creator Shinji Mikami served as the game's director, with development taking place at his studio Tango Gameworks.

[14] Initially, Mikami had no interest in making another survival horror game but after realizing there was a demand for one, he felt compelled to respond.

[17] Believing that the tropes of the survival horror had become predictable over time, the design deliberately attempts to make the player feel powerless by taking place in confined spaces, limiting ammunition, and presenting near-invincible enemies that promote running and hiding over engaging in combat.

[18] Art director Naoki Katakai said that the design concept of enemies, such as those wrapped in barbed wire or filled with glass shards, is that they are victims suffering under a greater evil.

A story-based campaign following Kidman was released as two separate DLC packs, which introduced new enemies, locations, and focus on unsolved mysteries from the main game.

"[38] Polygon's Philip Kollar summed up his thoughts by saying: "The Evil Within has great moments where the excellent combat and creepy environmental design come together.

But those moments are fleeting, inevitably sapped of their delightful terror by design choices that feel trapped in the glory days of a decade ago.

It artificially forces players into punishing combat scenarios more times than can be ignored, and plots and themes with great promise end up sputtering out in disheartening fashion.

Between a gorefest that's thoroughly engrossing, amazing feelings of triumph created by the imposing difficulty, and a plot that gets to the core of some very unsettling themes, The Evil Within brings enough to the table that it deserves a taste.

"[47] Christopher Livingston from PC Gamer gave it a mixed review, praising the survival portions of the game, tense and often exciting atmosphere, satisfying stealth, exciting action sequences, as well as the nicely detailed environment, but criticizing the recycled, and very often, not scary bosses, poor character models, late texture pop-ins, sluggish control, frustrating camera angles, limited video options and poor decision on the aspect ratio.

[50] Tim Turi from Game Informer praised its high replay value, jump scares, well-executed lighting, dark, unpredictable world, as well as the sounds of enemies, but criticizing the distracting texture pop-in and disappointing story.

He summarized the game as "an unnerving experience that keep your palms sweaty while delivering a harrowingly rewarding gameplay trial.