Really cool idea! I'm not very familiar with Backrooms games in general, but I imagine their charm comes from the liminal feel and how nothing seems to end. I definitely felt that with this. It’s maddening to keep walking around and around, and I like that concept.
I'm not sure if the super crazy screen effects were caused by me killing myself too much, but it’s almost impossible to find the door, though I did give it a real effort, so I’m not sure if there’s an actual ending. The effects feel a bit too intense, so I think we could tone them down a little.
I like the MC’s design. I do wish he talked a bit more, but it probably wouldn’t work well in this format and might be hard to implement. Still, I think it’s a neat idea.