The Backrooms Wikidot is this page here. It shows all 999 levels, entities, has a huge social community, and very organized, high standards. Imo, this is "the best" adaption of the backrooms, as the higher standards lead to better content. If a stranger asked me to describe the Backrooms, all of my info owuld be based from here. This is simply an opinion, however.
The Kane Pixels adaption of The Backrooms is much different. The Backrooms serve as a containment space, with levels definitely based on popular liminal spaces, such as the Poolrooms. There is also that one entity, The Parasite, I think? This world is much smaller than other adaptations, plus, is mainly set to be shown on Youtube. I think that this one is fine, especially because it has caused this wiki to grow stronger with more people.
Now, The Backrooms Fandom. I think that this one, quite frankly, just doesn't have very high standards. Instead of raising the bar every article, they just graze it. Is this a problem? Not really, but this is a much more unorganized, low-quality showing of The Backrooms. They do have many different levels than this wiki, level numbers going into thousands, and that is pretty cool.
I exist for the sole purpose of writing this
