Alright then, what are ideas people have for plot? Now, this most likely to be a scary game, we'd have to have the protagonist be kept in the dark for 90% of everything there. Fear of the unknown is one of the most potent, and it allows us to avoid exposition.
We'd also need characters for them to interact with, such as scientists, security, D-class, civilians, all real people with real reactions to being horribly slaughtered/mutilated/sent insane/set to the realization of a vast and uncaring universe. They'll have a wider palette than that, but these characters will have to react realistically to incredibly high stress situations and more.
Then location, and event. Is it a research facility? Pure containment? Is it built around a particularly dangerous, immovable SCP? What's the collateral damage if this place disappears? What's the event? Attack by a rival group? SCP breach? Traitors? Natural disaster? Or even just a normal day at the facility?
And finally, last but not least, we need a collection of SCPs. Now, this being a game, they'd have to be different somewhat from those on the wiki. More… practical isn't the word I want to use, but they have to be interesting and capable of interacting with the storyline as such. Basically, they don't have to be standalones like the rest of the wiki, but that doesn't mean that they're allowed a dip in quality.
tl;dr BRAINSTORM LIKE A BAWS