Warlock: Master of the Arcane
For the purpose of simplicity, let's start by saying that Warlock is basically a fantasy-themed Civilization V. Which is pretty awesome! Warlock is a hex-based, turn-based strategy game, with empire building, research, unit combat, diplomacy, and multiple win conditions (set in the world of Paradox's Majesty series, which is apparently a thing?). There are some meaningful mechanical differences, though, which make Warlock play pretty differently.
For one, the research concept is pretty simple in Warlock. Instead of researching technologies in a tree, your Great Mage can research from a selection of magic spells; unlocking a spell - which may deal direct damage, heal a unit, apply some buff or debuff, or even alter the landscape - just allows you to use it. This research has no effect on how your empire or units in general operate. The closest Warlock has to that kind of mechanic is in the buildings you construct for your cities, which follow (fairly small) trees and enable the construction of new units or acquisition of more powerful effects.
One really cool feature in Warlock is that some buildings unlock perks, which you can purchase on any individual unit fitting an appropriate type (that is, some perks are unique to e.g. ranged units). What this means is that, once your buildings are constructed, you can instantly get upgrades for any new or existing units, on an ala carte basis -- maybe you're only interested in buying perks for your front line, or in buying defensive perks for the time being. It's a cool approach to ability upgrades, and since Warlock also has more traditional (well, Civ-like) mechanics like unit-type upgrades and perks unlocked from level-ups, the purchaseable perks don't feel like they come at anything's expense.
Empire building is pretty different too: unlike in Civ V, founding and building out new cities is quite easy, and in fact the best way to meet rising population and army requirements is by founding new cities like nobody's business. This feeds quite well into Warlock's sense of exploration and adventure, as you rapidly push the boundaries of your empire ever outward.
Which is especially important because of the ravaging forces of unaligned monster units in Warlock's game world. A far cry from the relatively tame Barbarians of Civ V, Warlock's monsters spawn from capturable factories, and at random, and will both guard precious resources and wreak various levels of havoc upon your cities. Monsters can found cities, and can even capture the cities of other Great Mages. Personally I found the monsters even more fun to fight than the AI players, since the AI is - at least on Normal difficulty - pretty retarded.
There are plenty of other cool features in Warlock too, like alternate planes (smaller maps which you can teleport to and from using special portals), multiple races with unique buildings and units, recruitable hero units, and a bunch of gods with which to curry favor or disrepute. Actually, one of the possible victory conditions is to become so hated by a god that you must fight his avatar. Suffice it to say, Warlock's mechanical complexity is very satisfying, and the map is a blast to explore and conquer.
But there are big problems with the game, which mostly come down to a lack of polish. Some aspects seem pretty unbalanced, like the amount of gold and mana you can earn with some basic min-maxing on your empire structure. As aforementioned, the AI is basically incompetent, to the point where they're more likely to harm you by accident than on purpose. And the game is buggy -- button clicks will not-uncommonly get lost in some nether-world UI layer, and a clear resource leak leads to deteriorating performance as turns proceed, ultimately resulting in frequent crashes (I crashed five times in the course of my nine-hour campaign). This seems to be somewhat expected, as the game auto-saves every turn, and the startup screen features a Continue button, so you can swiftly recover from a crash with minimal losses.
Summarily: Warlock is pretty damn cool. But, even more so than Civ V, technological infidelity holds it back. The game is already pretty cheap, though (and there's a Steam demo), so if the idea of a fantasy-Civ appeals to you, definitely check it out.
Better than: well, about as good as Sid Meier's Civilization V, though lacking in terms of real AI competition
Not as good as: Sid Meier's Civilization V: Gods & Kings
Also, one feature I really wish for: the ability to continue a campaign after winning. There's so much to do in Ardania, and my last victory was literally an accident.
Progress: Finished a campaign on Normal