The Dark Mod won PC Gamer's coveted Mod of the Year award back in 2013, and has went from strength to strength since. Its latest update adds "hundreds of new high-quality models and other assets", a new mission editor, and a new introductory level.
Inspired by Looking Glass Studios' original Thief game, The Dark Mod was originally a Doom 3 mod, however is now a standalone platform that boasts over 100 community-made missions. That library can be viewed in full in this direction, however the latest update, number 2.05, showcases what's new via a new introductory mission—the first of three planned story levels.
"Many of these new assets are showcased in a new introductory mission for The Dark Mod that is included in the update," reads an update post on the mod's site. "This mission is the first of a three mission story which serves as our official introduction to TDM’s gameplay and setting. You should notice an increase in performance speed in TDM 2.05, thanks to rendering improvements made by duzenko and nbohr1more. Grayman has also added a working fire elemental to our list of available AI opponents that will no doubt appear in future missions."
Full details on version 2.05's changes can be found over here, however much of what's new is also detailed via the following trailer: