The Kefrens demo "Desert Dream" was to include 2 hidden parts.
The second one being launched from the first one.
I had contact with the Kefrens members, and this is now confirmed.
You can read their messages here : http://eab.abime.net/showthread.php?s=&threadid=10231
Unfortunately, due do a bug in their key-trigger / loader routine, the second one can't be accessed at all.
It is unsure whether to code is still intact on the released disc, but I am convinced it is, read below.
I had a close look at the disc #2 usage using WinUAE and here is the result :
"Start of part 2"
"Sinedots 3D (continuation)"
"Cooper Anim - Ending credits"
"Hidden Part 1 Start"
"Hidden Part 1 Cooper scroll"
"Hidden part 2 ???"
Track 58-59 ???
As you can see, for the hidden part, they load bunch of tracks in reversed order.
The track 19 till 57 seems to contain garbage only.
Among other things I saw there servial versions of a tool named "RAM-TEST" by Markus van Kempen, copyright by GIGATRON; together with piece of source code.
The interesting part lies on track 58-59.
There, you can find a small chiptune module (13 Kb large, was ripped and spread years ago by Sven Gester).
Around that module there are some machine code that must actually be the hidden part #2.
Now, here is the end of my Amiga knowledge.
I was coder/cracker on TRS80 Color, Amstrad CPC & on early PC, but I only used Amiga for gaming or demo watching.
For an experienced coder / cracker, it should be pretty easy to figure out the right memory address to load those tracks, and run the code.
This part maybe re-use some code already loaded by hidden part#1, as ~22 Kb, including a 13 Kb module is maybe too short.
To the person that are willing to help us, don't forget you will bring back a piece of history to all the Amiga fans.
I am sure you'll be praised till the end of time for doing that
Sorry for the long message.