(I post this guide just as a report of some recent findings about the game)

In Descent 3 there's a possibility to record in game demos (default key f5). They're not videos but simulations in the game engine. For some reasons it's possible to save and load while watching a demo, and this can glitch the game in some ways that might be useful for a speedrunner.

In his tutorial video on the subject, d3maniac explains how to exploit the glitches and use them as a teleportion, and to get out of bounds :

He gives two methods:

• recording a demo of yourself loading a level (achieving a coordinates shift)
• loading a level while watching a demo (achieving a level shift, or let's call it parallel universe trick because it sounds cool)

I tried these methods in the whole game and so far I found that the following skips exist:

• (NEW) lv2 fully skippable from lv1: in the upper room of the first building
• lv4 tube section skippable to reach the sewers directly from the spawn point of lv1-2-3
• (NEW) lv4 tube & sewers skippable to reach the final part of the level, from lv1: in the upper room of the first building
• lv5 fully skippable from the spawn point of lv2
• lv6 boss room reachable from the spawn point of lv3
• lv8 fully skippable from the spawn point of lv5 or lv6
• lv10 final C.E.D. reachable from the spawn point of lv1-3-6
• lv11 fully skippable from the spawn point of lv6-9
• lv12 fully skippable from the spawn point of lv5
• lv15 lava countainers room reachable from the spawn point of lv2-10 ... and there might be a lot more...

At this point I guess the speedrun can be divided in two categories, either use this trick a lot and go full OOB, or trying to actually run the game without skipping too much of it (of course, skipping the level 5 would be fine, as nothing happens in it anyway)

But there's more to it, because you can also use the demo glitches to backtrack inside a level. I show how in this video:

Once again this possibility splits the run in two categories, either use this feature or not.