The Pathways into Darkness demo became available to download from America OnLine on Jul 7, 1993. The Read Me file refers to the demo as Demo Version A1: 7/2/93. It came with three levels:
Pathways into Darkness... and its Reprise
Never Stop Firing
Witness Total Carnage
None of the maps would appear in the full game and only the level name "Never Stop Firing" would be reused. We do know from the original level name section that the name for the first level in the full game was originally "Pathways into Darkness...". Furthermore "Witness Total Carnage" was the name given to one of the Official Screenshots. However the sceenshot bears no relation to the demo level.
Some interesting things about the Demo Version A1.
There is a Climb button and you have to use it to climb up or down ladders. This feature (restriction) was removed in the full game. It does however indicate that the infamous Pathways Screen Shot was orginally taken from a version of PID where climbings was still implemented (note the climb button). See the Official Screenshots section for more details about the 'fake' Pathways Screen Shot.
The Demo Read Me reveals that the amount of time you were going to be given to complete the full game was originally planned to be much shorter.
The game starts at 6:13 AM on Sunday morning. You must detonate the nuclear device before 2:00 PM on Wednesday to complete the mission. In addition, keep in mind that if you wish to survive, you must escape to the surface and signal the extraction team with a radio beacon. Allow ten minutes for pickup, and another ten minutes to reach minimum safe distance. Also, keep in mind that resting takes up a lot of time. Try not to rest too much.
Thankfully in the full game Bungie give you until 2:00 PM on Friday to complete your mission. Someone obviously realised it was going to take you a lot longer to finish the game the first time round.
The Demo Read Me also mentions the Yellow Crystal and while you do find dead Germans on two of the demo levels you can't talk to them since there is no Yellow Crystal.
It is not known how many kinds of crystals you will come across, nor what the effects of most of them are. The Yellow Crystal allows you to talk to dead people.
What would they say if they could talk? If you hack the demo to give yourself a Yellow Crystal they still won't talk. Apparently this feature wasn't implemented in the demo. You can find out that the dead Germans say if you have ResEdit and some patience. Check the Conversations with the Dead section.
In the demo the dead Germans are given a rank. When you walk over the first dead German the Message Window reads You see a dead German private. One of the two dead Germans on Never Stop Firing is an 'officer'. The rank of the Germans was removed in the full game.
In the Pathways Demo vA1 you could save anywhere you liked. In the release version (v1.0 and v1.1) you could only save at a 'saved game' Rune. Jason Jones gave these reasons for why he changed the saved game system for Pathways between the demo and the release version. See the Undocumented Features section for what Jason did in Pathways v2.0.
In Hopper's Annotated Maps for the Demo vA1, the first level contains a room which doesn't appear to be accessible in-game, as such it doesn't map. Of course you may know different.
While there are only six Crystals in the release version of the game, the Shapes file of the Demo vA1 contains a seventh Crystal.
This is the mysterious Blue/Yellow Crystal. No details are available about its oddly combined heritage.