Descent to Darkness is the second episode of ZPack - Random Maps for ZDoom. The episode is more difficult than its predecessor, but not as difficult as the final episode. On the whole, the maps are also larger than the maps in The Remains of UAC. The episode is composed of mixed themed maps, bouncing from fairly normal UAC outposts to bleak stone fortresses. The story "excuse" for the changing themes is that the player is traveling through dimensions, on their way to Hell.
After the decision that maps would be ordered primarily by theme, it was clear to the ZPack team that most of the techbase maps would be towards the beginning and most of the hell maps would be towards the end. This left the fewer alternatively themed and mixed themed maps to take up the middle, which eventually became the second episode. The varying themes nature of this episode is perhaps best exemplified by E2M1 and E2M6, both of which are multi-themed maps whose themes change abruptly and almost arbitrarily.
Notable stops along the player's journey to Hell include: a twisting city like location filled with unusual combat circumstances (E2M3), a rusty, otherworldly structure with churning parts and rotating fans (E2M5), and an out of the ordinary mini-adventure with more than just your usual combat (E2M0).
- E2M1: Switchback, the Three-in-One Remake by Phobus
- E2M2: Ultimate Insanity by InsanityBringer
- E2M3: More Tricks and Traps by Daniel Gimmer (Tormentor667) (Exit to secret level)
- E2M4: Command Center by IcyTux & Tuxido666
- E2M5: Fanboy by Albino_Rhino AKA Jason Farlow (farlowj)
- E2M6: Terror Cube by Zippy
- E2M7: Black Inferno by Daniel Gimmer (Tormentor667)
- E2M8: Tearing 'N' Temptation by IcyTux
- E2M9: Abyss to the BBQ by Daniel Gimmer (Tormentor667) (Boss level)
- E2M0: For the Hell of It by Phobus (Secret level)