"Levels having up to ten times the size" can also translate into massively increased detail. Many D2X-XL levels utilizing the increased amount of segments (like Pumo's "Kartsal Motivation" demo, Yokelassence's "The Sphere" or my mission "Boiling Point") rather use them for that than for making the levels more expansive. Sirius "Anthology" and Yokelassence's "Dimensional Intersect" on the other side have just massive dimensions, but also are tremendously thrilling and fun to play. I recommend to play all these missions before making a judgement here. :)
The Vertigo data indeed isn't included in GoG's Descent 1+2 data (I wonder why that is), but if you ask around in the D2X-XL forum, someone might help you with that until GoG changes that (which I hope they will do - I have prompted them to that issue already, and as far as I know them they are very constructive guys :)).
@SladeStrife,
D2X-XL replaces the original program, but you still need to own the original game data.
@DukeNukemCZ,
D2X-XL just issues a warning about these files not being present, but you won't need them to play Descent 2 missions. I have added that feature (of D2X-XL warning about missing files) because so many users complained about not being able to play D1 or Vertigo levels with it and couldn't figure why; so D2X-XL tells them that certain files are missing in the hope they will understand that due to that they will not be able to play missions requiring them.
@Smannesman,
D2X-XL comes with a useful options preset, and music, movies and high resolutions work out of the box there, too (D2X-XL even automatically choses the highest native resolution your hardware offers). These things are just a matter of course.
But what do you want? XL also has way more features, and I have boiled the options down to the essential ones anyway - and there have still been a lot of people complaining that I have removed some of the more technical options. Those that are available allow every user to fine tune D2X-XL to his hardware, and most users appreciate that (Rebirth may not need that due to its low requirements, but that also means it doesn't offer much in terms of visuals or additional gameplay). D2X-XL's options are also nicely grouped into rendering, effect, gameplay, physics and effect options. That's not so many options that you would get lost in them. Above that, D2X-XL has an integrated help function: Press F1, and an explanation of the currently highlighted option will be displayed.
@ShadowCat,
I find it unfitting to post Rebirth advertisements here. The only reason I had posted in the Rebirth spotight was that GoG.com had used D2X-XL screenshots to garnish it (and I only posted there two years after it had been published).
@All,
The following Youtube videos will give you an impression of how it is to play Descent with D2X-XL:
Descent 1: First Strike level 1 Descent 2: Counter Strike level 1 Descent 2: Counter Strike level 2 Scenes from D2X-XL levels