- Ascended Fanon: When SCP-049's article was rewritten in May 2018, the character's Affably Evil persona from Containment Breach was made canon (as opposed to the Silent Antagonist he used to be) and the writers even brought back TheVolgun to become his canon voice actor.
- Colbert Bump: To say the game increased awareness of the source material would be an understatement. According to the wiki's "History of the Universe" essay:"The arrival of Containment Breach was the most powerful event to impact the wiki. Never before had one thing created such an influx of traffic, recognition, and new users. [...] We went from having 50 applications in a month to having that many every day. That number kept up every day, and resulted in the number of new articles being posted increasing dramatically."
- Creator Backlash: juanjpro, the creator of several SCPs for the game, has cited SCP-1074 as being terrible and "embarrassingly bad", despite having created it. It was eventually removed, its role in showing a backstory for D-9341 was replaced by SCP-1162, which lead to him being changed from a former mass murderer to a demoted Foundation employee.
- Official Fan-Submitted Content: Some of the SCPs in the game started off as fan mods before becoming official. These include SCP-008, SCP-178 and SCP-500, among others.
- The Other Darrin: SolidBaker was the original voice of Security Chief Franklin and the broadcast voice that announced the breach, although they were likely intended to be the same character early in development. They were later recast to DukeLovesYou in version 0.3.
- The Original Darrin: SolidBaker's voice, however, remained in game occasionally being heard on the radio continuing to announce the breach. While DukeLovesYou remained as Franklin ever since his voice was implemented, in 1.0.0, Franklin could now be seen exiting a room alongside Agent Ulgrin to avoid SCP-173. Likely not able to be in two places at once, DukeLovesYou's broadcast voice was retired in 1.0.6, which restored SolidBaker's voiceline as said voice.
- Talking to Himself:
- Voice actor/reader for SCP TheVolgun voices both D-9341 (specifically when under the effect of SCP-012) and SCP-049, the Plague Doctor, as well as Evil Mask SCP-035, one instance of Voice Changeling SCP-939, and Dream Walker SCP-990. He also voiced a scientist and janitor in a storeroom where both are killed by SCP-173, an MTF Unit who guns down D-9341 when 049 has turned them into an 049-2, and the facility's PA System.
- Voice actor ItsDuke does this for a large variety of characters in game, mainly as various guards, the MTF units that pursue D-9341 throughout the game, as well as every character that speaks at Gates A and B, and even the different characters who speak on the ending screens.
- Another voice actor, DukeLovesYou, voices Agent Ulgrin, Security Chief Franklin, two other guards (one at the Class-D cells, another on the balcony in SCP-173's chamber), and another SCP-939 instance. Ulgrin and Franklin directly talk to each other in a sequence where they can be seen escaping SCP-173 shortly after the breach begins.
- The Wiki Rule: Yup, its got one. A wiki about a game about a wiki.
- What Could Have Been:
- SCP-689 was going to be in the game but the creator decided against it, most likely due to the fact that it's Purposely Overpowered.
- SCP-650 was also under on the radar of the community for a short while. The dev even said he would implement it should someone complete a full model of the SCP. However, any attempts at creating the model have wound up being cancelled. It was later added to the Unity remake of the game.
- SCP-513 was also implemented into early versions of the game, before being removed shortly after. It was re-added years later with completely different functionality. To elaborate, the player never originally encountered 513 directly, but the intercom would play the sound of the bell ringing, leading to the player occasionally seeing 513-1. Its role in driving paranoia in the game was eventually given to SCP-372 in its place. Said different functionality once it returned involved the player finding 513, being able to ring it in their inventory, and then 513-1 could be hallucinated, though 513-1's model was different from in the older versions (the face of the old model is used, however, as a hallucination by SCP-895).
Trivia / SCP – Containment Breach