I bought Warlock 2 during the Summer Sale, and I've quite easily gotten my money's worth. It is a lot of fun, though not without serious flaws. My review is based on three (partial) plays of "The Exiled" story mode, and one full playthrough in "Battle for the Outplanes" mode.
A big complaint a lot of people have is that it seems like a content update, rather than a sequel to Warlock. This is true to an extent. However, the handling of the planes was the biggest flaw of Warlock 1 but seems to be the central appeal of Warlock 2. In Warlock 1, there were other planes, and they were full of big bad monsters, but they weren't very interesting and the rewards for going there weren't significant enough to bother with them. A game of Warlock 2, on the other hand, has a hierarchy of planes, where you (and your A.I. opponent mages) start on less threatening planes, and you work your way down through to planes with significantly more dangerous fauna (and sometimes flora), or back up the hierarchy to fight the other great mages. Each plane has its own unique flavor, and most special resources only occur in one or two types of plane. The special resource thing is key... most races don't have strong research-producing buildings, so you need to chase after the research-producing resources, which tend to be a couple planes down from where you start. The first time I reached a Shadow Plane, and established a fortress there to defend myself against the horrible shadowy horrors that awaited me, it felt ... well... I would say "epic", but that word is way overused these days. But it was awesome.
I was also impressed with how much the game made me care about terrain, and provided a multitude of terraforming spells that I actually want to use. The ability to throw up a mountain where I want a defensive chokepoint, or to raise up a landbridge when I want to cross an ocean is quite empowering.
The big flaws of the game, are that the AI is quite poor (and the game is pretty easy in general), and that the game gets tedious once you have a big empire.
Planar portals provide your primary military chokepoints in the game. The A.I. takes advantage to this to an extent, in that it's smart enough to build fortifications on its side of a portal. However, it's really bad at launching offenses through portals. If you stay perpetually at war with an A.I., it will continually send a trickle of one or two units at a time through the portal to be slaughtered on the other side. The only threat the A.I. can pose, is if you let it build up during peacetime, and send a large number of units through at a time. If you let this happen, A.I. units will pop up in funny places as they exit at the nearest unoccupied hex on your side of the portal.
The late-game tedium arises mostly from troop movements. Moving troops across your empire takes an awfully long time when you're spread out across several planes. I don't trust the pathfinding of the game to do it for me, as it often works rather poorly (though this is somewhat understandible technical hurdle, given the many movement modes of units, as well as all of the terraforming). One thing about the game alleviates some of the late-game tedium though. You are limited in the number of normal cities you can have at once (starting at five, and increasing with research). But you can also have an unlimited number of special cities, which are less beneficial than a normal city, but require no management. Managing cities doesn't become a slog, because you typically only have 5-10 of them that ever need any attention.
The story mode ("The Exiled") is cool the first time, but is essentially the same each time you play.
My plays thus far:
1. Exiled Mode, average difficulty, small multiverse, two opponents. I was friendly with the other great mages and focused on the storyline. I had a lot of fun exploring the game for the first time, but ultimately got bored while fighting through the penultimate plane (which is full of tough monsters, but is way too big and unvaried to hold my interest) and quit.
2-3. Exiled mode, hard diffuculty, small and medium multiverses, max opponents. Did some conquering of great mages and had fun conquering my first few planes, but ultimately got bored.
4. Battle for the Outplanes mode, impossible difficulty, small multiverse, two opponents. I played this one all the way through . I had quite a bit of fun with it, but was overall very dissapointed with just how easy I could conquer the "Impossible AI" opponents.
I'm off to try Sandbox mode next. I'm hoping the A.I. will handle it a bit better.