Please note: all credit goes to Airglow!
This is a small guide for those people who want the achievement Lost inside the Backrooms.
How to Obtain Lost inside the Backrooms Achievement
Conditons: You should be familar with the normal ending, the pool and the office rooms. I wont explain how to do the office or pool so do the “normal” run first.
Sidefact: This level is known as “Run for your Life” level.
So now that you know this lets start.
The New PC Code
So after you got through the pool, you will enter the next room. You will see a red door which leads to the last room before you are getting the normal ending. Don’t go through this door. Instead look at the ground and you will see a gate which will lead you to the right way for this achievement later. First you have to look for a note which also lays on the ground in this room. It will tell you in which order the symbols are for the new code.
Now that you know the order look for the letters at the corner. They will look like this.
If you put the letters in the right order you should have a four letter code now.
Go back through the pool til you reach the main pc in the office rooms again, after you turned the electricity on again.
Go back to the pc, delete the “Unlock Success” and enter your four letters. You should get a notification which will says “Security Door Unlocked”.
Turn the electricity off and go back through the pool.
The Long Red Floor
Now you will see that the gate has opened and the room looks like this.
Jump down and you can read a note which tells you that you should run as fast as possible.
You need “Mouth Jelly” or you will die pretty many times.
You will start in this long red floor with many obstacles.
When you start to run this new creature will hunt you so damn fast.
So don´t look back and keep running.
After you get through the obstacles, there will be a lot of doors at both sides.
The doors will open by themselves and some long arms will try to grab and kill you. So try to dodge to the left and right side at the right time.
At the end of this long walk are two exit doors which lead you in the final room.
You are now in a room which is quiet empty and you have no other possibility then jump (as far as i know).
After you jumped down, there will be a cutscene which shows your dead body which will be found by two other survivor. You get the screen with “You get lost Inside the Backrooms”. Close your game and there is your new “Secret Achievement”.