Warlock: Master of the Arcane - Armageddon
The Armageddon DLC adds a new game mode to Warlock, which turns some seemingly simple mechanical alterations into a dramatically different campaign experience. While a normal campaign plays primarily against other Great Mages with the unwelcome interference of monsters, an Armageddon campaign gives the monsters (and landscape) enough power to flip that balance around.
Rival mages are barely a concern, as Dremer invasions randomly spring up, infecting the landscape (which reduces all of your resource income), and even destroying a city instantly if you're unfortunate enough. Not to mention the random appearance of volcanoes. The default win condition in Armageddon isn't victory over your rivals at all, but to defeat the Dremer invaders at their source.
It's an interesting mixup, but even though fighting monsters was one of my favorite aspects of the normal campaign, I found Armageddon's Dremer to be a bit too much. It was all I could do to fight off random spawns before new ones came in; my empire developed so slowly, that I had to rely on hero units to do basically anything, and never really made any headway in exploring the world to find the Dremer's anchors or whatever.
More so than Warlock's regular mode, Armageddon is let down by imbalance. Maybe some future patches will make the mode more palatable, but until then, the absurd, destructive difficulty doesn't seem worth putting up with.
Better than: a lot of other crappy DLC that just adds items no one really wants.
Not as good as: Warlock: Master of the Arcane
At least it's super-cheap: and adds some new Great Mages to the regular game, too.
Progress: Gave Up -- Built a basic empire, but keep getting warlock-blocked by Dremer