A site-wide broadcast then announces that several SCPs have breached containment, forcing the site to be put under lockdown. SCP-096 attacks after the player viewed its face.Дuring this testing routine, the site's power and door control systems begin to malfunction, allowing SCP-173 to kill the other two test subjects and escape into the ventilation system while, by player control, D-9341 escapes the containment chamber. The player takes the role of D-9341, a Class-D test subject (usually inmates on death row, who have been drafted to work for the SCP Foundation) who is forced along with two other test subjects to perform tests on an SCP known as SCP-173, a concrete statue that can move at high speeds and attack by causing cervical fractures at the base of the skull or strangulation when not in the direct line of sight of a person. A Foundation task force known as Mobile Task Force Epsilon-11, designated Nine-Tailed Fox is deployed shortly thereafter to defend this site from any more breaches in containment. At some point before the events of the game, several of the Foundation's containment sites are attacked by the Chaos Insurgency, a rogue element of the Foundation, forcing the relocation of many SCPs (the designation given to their contained anomalies) to an unspecified site. The game revolves around the SCP Foundation, a secretive organization dedicated to containing any anomalous artifacts, entities, and locations that threaten the normality of the world. They may also encounter benign or inanimate SCPs. These include tools such as gas masks, various electronic devices, batteries, and keycards of various levels for operating locked doors. These soldiers are armed with FN P90s and will shoot the player when detected.ДЄlong the way, the player can find a wide variety of items to assist them in survival.

The game becomes gradually more difficult as the player progresses and the Entrance Zone marks the appearance of Mobile Task Force Epsilon-11 'Nine-Tailed Fox', a squad of elite soldiers deployed by the Foundation to recapture the breached SCPs either by re-containing them or by destroying the facility by detonating the nuclear bombs situated throughout. Some SCPs may appear throughout the entire facility, however. New SCPs and artifacts may appear in one map, but not in another. One of the game's primary features is randomly generated rooms. Another one of these SCPs is SCP-096, which will kill the player if its face is viewed, but otherwise will remain docile. Certain environments (such as rooms filled with decontamination gas) will cause the player to blink more often. The player is pursued by numerous hostile SCPs, which must be evaded by D-9341 to avoid death, which is made more difficult by the player needing to blink periodically, enabling SCP-173 to attack if it is nearby. The player controls a 'Class-D' personnel as he attempts to escape an underground research and containment facility operated by the SCP Foundation amidst a total containment breach of its hazardous anomalies, designated 'SCP's.

Scp 035 containment breach