Here is what Sirius himself has to say about his level:

Anthology started, as well as I can work out, in about June 2005. The mission: to make an interesting, straightforward D1-style co-operative level that I could play with some people when we had a bit of time to kill and wanted something new. At the same time I would get to use some ideas I'd never found the opportunity to use before.

A couple years - and then some - have come and gone, and the aim has changed substantially. Two things happened; firstly D2X-XL raised the segment cap for Descent 2 levels to previously unheard of highs, and I decided that this level should be the one to exploit them. Secondly, I found an idea that would put that extra size to use. Now Anthology has a different aim: To provide the player with a trek through the Descent series, and to do it in a single sitting - even if pretty much all of one.

Like Descent, you will start in a mine deep underground, and fight your way through twisting corridors, rooms and lava caverns. You will ascend through the mind-bending puzzles and structures of Descent 2, until you reach the surface of Descent 3. All the while, you'll see the familiar enemies, architecture and environments that brought these games to life. It won't be an easy fight, but I trust it'll be an enjoyable one!

And now don't waste any more time: Get it and play it!