Wonderful old scifi short story I need help with !

[Baarp]

Hello all,

I'm hoping some of you well read scifi people can help me out !

Many years ago I read a great scifi story that I am trying to find the author and title of.

From what I can recall the story is told from the perspective of a case report filed by a police officer. The report begins with a brief introduction saying that they went to the house of a man who had been reported missing and they found a note on his floor. The rest of the case report and story was a copy of that note. The note went something like this:

"Please do not be alarmed by this note appearing on your lap. In a few seconds, you will be transported to another dimension, where you will take part in events of increasing difficulty.

The first event will consist of you running down a long tunnel as the tunnel closes in behind you. Upon reaching the end of the tunnel, there will be a door which you will go through, and that will lead you to another tunnel. This tunnel will close in behind you faster than the last, and at the end of the tunnel, there will be two doors. One door leads nowhere, while the other leads to another tunnel, which will in turn close in behind you at a faster rate, and will contain three doors at its end. This process will continue until the 50th tunnel.

After exiting the last tunnel, you will be transported to the edge of a great ravine. Above this ravine will be floating disks of various colors. Some are safe to stand on. Others are merely holograms, and others yet, while safe to stand on, will amputate your foot. You will have to cross this ravine through a process of trial and error.

After crossing the ravine, you will be transported to a black place. In this place, your body will be held in stasis, meaning your will not need to eat, drink, or sleep, but your mind will still be perfectly active. You will need to wait in this place for a random length of time, varying anywhere between one-half of one second to several million years. How long exactly, not even We know..."

I also remember that at the start of each new event the instructions
state something like "you are the 2,364th of your kind to reach this level" - this number gets smaller and smaller as the feats become more deadly !

The story continues on like this through perhaps a dozen of these horrible sounding scenarios.

The last part of the story goes something like this.

"Upon completing this final event, you will be transported to a peaceful realm with all of the other survivors of this event. Your safety in this realm is not guaranteed, as you will need to coexist with species from other worlds and universes from your own, and they may be hostile after all that they have endured. You do have a choice though. If you wish to return to your home world you may do so, but you must go back the way you came."

This is just a rough adaptation of the story from memory. Does anyone have any idea at all? If not an idea about this story specifically, does this sound like any authors that you are familiar with? I'd love to find this story and give it a good read through again. If anyone has any ideas, I'd greatly appreciate it.

Many thanks !