This is a guide to help those trying to find every last secret in the backrooms. Huge props to the creator for hiding these secrets so well. It took me and my four friends 3 hours of searching to find the secrets. Hope this helps Anyone trying to enjoy all this map has to offer.

Secret Hospital Chase (Level 0)
When traversing the first main level of the Backrooms (level 0) or green normal room, you will come across on the perimeter a big open area. This is the area where you get the key to progress the story. Heading toward the section in the upper left with the holes in the floor simply jump down one. WARNING: This only works on the first attempt and any other player or person who falls down will simply die. Once in the hospital hallway run! A monster will chase you and kill you if it catches you. Keep running once you reach a green area. Multiple green areas will be reached before the end. UPDATE: reaching the end will now teleport you back to the last level you were in.

Level 27- (Wood Backrooms)
In the first level of the backrooms, the green normal room (level 0), toward the middle right of spawn there is a hidden invisible hole in the floor which you can fall through to get to the wood backrooms. Finding the hole is much easier with the flashlight off, as the rectangle hole can be much easier seen. It is in a T intersection, my advice, stay toward the middle not the perimeter to find it.

Worse than Death Ending- (Wood Backrooms)
After finding the Wood Backrooms (see above) you run around opening doors. Eventually one will teleport you into a tall city like location where an ambulance and hanging man are visible. You can either choose to escape and get the Worse than Death Ending in the ambulance (simply enter it) or move toward the hung man and go to the party room, which will teleport you back to the next level.

Level 1-(Parking Lot)
There is a secret escape to quickly get to the party room (more can be found in Worse than Death Ending). On the upper floor of one of the parking levels a large camp full of dead people and tents can be found. To the right of the blood written "Nobody is going to save us" and around the corner where you would come up or down, there are two wooden boxes stacked together to form a staircase. If you jump onto the boxes and get up where the barbed wire is you can follow it to the left and back wall (look for 9 smile mouth in a 3 x 3 grid) and will be teleported to the party room. You can play music on the radio but shortly after you will be re-teleported back to the same level.

Level 4- (Office)
There are two things you can do here they kinda count as secrets. 1) After entering the office turn right into a large room with office cubicles. In the farthest or back row a women can be found at the end. If you talk to her, she will give some dialogue about her troubles and then hang herself. 2) After entering the office turn right and there is a vending machine by itself next to another entryway. Interacting with the machine will cause loud music to play and enemies to spawn as well as give you weapons.

Secret American Psycho Hallway- (level 5 Hotel)
After entering the Hotel, level 5, you must find the room with toilets in them. Moving inside should teleport you to a long hallway full of Better Call American Psycho's face. This is simply for fun and no further affect. Getting to the end of the hallway returns you to another room in the hotel.

Hope this guide helps you! Big thanks to my friends who after finishing helped me find all the secrets. The other endings and levels already have great explanations on how to complete if stuck so go check them out in discussions.