Descent

Opening and End Cutscenes
Shotguns have tighter pellet spread when ADS
Underwater Combat
Buildable (with parts in randomized locations)
Black Ops III perk set: Juggernog, Double Tap 2.0, Speed Cola, Quick Revive, Mule Kick, Stamin-Up, Deadshot Daiquiri, Electric Cherry, Widow’s Wine
Working Solo Revive
Pack-a-Punch with Repack (for Black Ops III elemental effects)
Takeo’s Katana
Super Effective Stamin-Up
Mortars
Call of Duty 4, World at War, and Black Ops 1 Weapons
Custom Patriotic Camos (Weapon-Specific)
Your favorite 2 custom wonder weapons from Puns return!
Dive to Prone (“Dolphin Diving”)
Perk Machine Change
Black Ops III Health System (3 hit down without Juggernog, 6-7 hit down with)

Note: When ascending or descending while zombies are “alive,” you may encounter frame drops as the game attempts to determine the proper path for the zombies.
Known Bugs:

Sometimes images won’t load; exit level and re-launch map to fix.
Double Tap 2.0 appears to not work properly on certain weapons. No rhyme or reason as to which weapons in particular (know it affects wonder weapon and Remington 700). Possibly only occurs for limb shots. No clue why. Connection / frame rate issue?
End cutscene may not play. If this happens, go into your app data, open the Descent mod folder, open the Descent IWD file, copy and paste the end cutscene bik into main/video.
Apparently, sometimes the Repack is free?
Evidently, there’s co-op bugs?