The game starts out with D-9341, a D-Class personnel, in his cell. After picking up a document containing details of an "exciting one month-working period" in a top secret facility, a Guard opens up the cell and tells 9341 to come out and perform a test with SCP-173. As 9341 arrives, there are two other D-Class personnel. The Scientist will tell them to enter the containment chamber and approach SCP-173. Once inside, the chamber door will close, but will mysteriously open later. His voice will be cut off after saying the door controls are not working as intended and the room will black out, flickering back on when SCP-173 kills the 2 Class-Ds. The scientist announces a lock down for the whole facility, warning the site of multiple Euclid and Keter containment breaches. Trying to survive the horror of the containment breach, D-9341 (the Player) will encounter many different SCPs.
There's 4 levels in the facility, the first is the Light Containment Zone, which is where the Player starts. It contains SCPs that are not necessarily harmfull. It has the containment chambers of; SCP-012, SCP-173, SCP-178, SCP-205, SCP-372, SCP-714, SCP-914, SCP-939, SCP-970 (it doesn't actually have a containment chamber), SCP-1025, SCP-1074, SCP-1123 and SCP-789-J.
The next zone after the Light Containment Zone, is the Heavy Containment Zone . It contains more of the hazardous SCPs such as SCP-008, SCP-035, SCP-049, SCP-096, SCP-106, SCP-513, SCP-682 and SCP-966. Here you can contain SCP-106, as it is needed to achieve one of Gate A's ending, and also a more safer escape.
The 3rd zone is the Entrance, where most of the scientists resides at. It also connects to Gate A and Gate B. This zone currently has 1 safe SCPs contained there, SCP-294, which is used for nourishment purpose. The only main threat is the Mobile Task Force.
WARNING:THE FOLLOWING SECTION MAY CONTAIN SPOILERS ABOUT THE GAME
- Main article: Gate A
If D-9341 escapes by Gate A, SCP-106 will come out from the ground (if not yet contained) and Nine-Tailed Fox personnel stationed outside will activate the H.I.D. Turret to contain SCP-106. If the player hasn't escaped yet, a MTF unit will approach D-9341. If the player escapes, a group of Chaos Insurgency soldiers will take the player away and the game will end. The other ending occurs if the Player contained SCP-106 using the Recall Protocol. Upon entering Gate A, three MTF units will walk to you, capturing you once they reach the Player. They will announce that the Class-D has been found. The screen will black out, and the ending cutscene will play. The SCP Foundation logo will appear in the background. A tape will play, talking about the Player's demonstration of complete mastery of even the most unprecedented circumstances. The person (probably a scientist) was observing the Player's actions through CCTVs. He presumes if further testing is required to see if the Player should receive SCP classification. The tape cuts out there.
- Main article: Gate B
There are two endings at Gate B. If the player has not turned off the Alpha Warheads in the Warhead Silo before the player reaches the control room, a siren will sound and a bright flash from the warhead's explosion will cover the screen at the end of the countdown. After this, the SCP Foundation logo will appear. A radio transmission will be heard, as a radio operative from helicopter OH-6 requests the deployment of an MTF unit to scout for remains at ground zero. However, the transmission is cut-off mid sentence as a large roar is heard, indicating that the nuclear blast was unsuccessful in destroying SCP-682 .There might be another gate/ending in a video called "Is there a Gate C?".
- Main article: Developers
Joonas Rikkonen (Regalis) and his group of developers created this game with the Blitz 3D engine. The game is currently only for Windows and the music is composed by Kevin MacLeod and Tim Morrison. Aaron Mckee (commonly known as TheVolgun) contributed a great deal to the development of the game by being a voice actor for several characters including SCP-049, SCP-990, D-9341, the scientist and guard in the first room and an MTF unit found in a SCP-049 cutscene.
- Main article: Versions
- 0.1 - The first downloadable version. It included the basic mechanics and had some of the SCPs.
- 0.5 (Halloween Update) - In this update, SCP-173 could have a new look via the Console Commands. It also fixed some models
- 1.0 (Main Release) - Added in SCP-066, SCP-860, SCP-939, and SCP-970. It included new models, new sounds, new music, and a harder difficulty.