I found a backrooms!
On a 5th floor

Walk through a wall at the top of the stairs on the 5th floor to the backrooms

these are sorta obvious ones to know and easy to find but on the first floor by the door there is a record player. then by one of the pillars on the first floor there is a knife and some blood

i made the record player start playing then it forved me to turn around and i saw a gimse of a figure then my game crashed

5 Easter Eggs :
- a knife
- shadow silhouettes
- a secret room on the 5th floor near the stairs
- an inaccessible corridor
- And the traces of blood in the secret room once all the rooms are open

I've just ?

You can see dark figures trough a window

Another thing to add on, it looks like if you destroy the record player a lot more blood is around, I destroyed the record player after opening every room and if you check the backrooms area on the 5th floor stairwell, you can see a large amount of blood by the wall at the end. I didn't check that out yet because it creeped me out too much, but I'll try again later

引用自 Retro X：

5 Easter Eggs :
- a knife
- shadow silhouettes
- a secret room on the 5th floor near the stairs
- an inaccessible corridor
- And the traces of blood in the secret room once all the rooms are open

I've just ?

Inaccessible corridor?

Yes, there is a corridor where there is no door to access it. You must activate the "No-Clip" Mode Toggle to see it.

i clicked e in the backrooms and nothing happend

I've only seen three shadow figures and they all leave blood
one around a pillar after you start the record player
one around the left corner on the first level
two in a window at a certain height level

引用自 Retro X：

Yes, there is a corridor where there is no door to access it. You must activate the "No-Clip" Mode Toggle to see it.

Where?

Hitting the record player with your crowbar causes blood to spawn all over the area, but once hitting it the music won't play anymore.

there two rooms with noting in theme

引用自 Fieldman15：

引用自 Retro X：

Yes, there is a corridor where there is no door to access it. You must activate the "No-Clip" Mode Toggle to see it.

Where?

On the ground floor, the same floor as the record player. You know how there's a hallway which the shadow guy pops out at you? Well, go to the opposite side of that, against the opposite wall which has nothing but windows on it, and noclip through and you will be in one of the rooms in said hallway. Nothing much interesting inside the rooms or hallway, however it is interesting that it's inaccessible.