I played the first overlord, and the OL2 demo (ps3). I'm surprised how many people posting haven't touched Overlord are already declaring the game bad. It's not for everyone, sure, but it's far from fun. It's a hoot if you're easily amused.
The whole game delivers tongue-in-cheek humor with its game play. In OL1 and OL2, the greatest source of souls (that translates into your minions) are woodland creatures (sheep) and other cute things (baby seals). It's not delivered with brutal realism, but rather a shiny grim sense of humor.
In the OL2 Demo, you're stalking a Yeti in the frozen...somewhere. An eskimo gets between you and the yeti, and declares it his find. The yeti smashes the eskimo and slaps him into orbit. Elves interfere with your killing of baby seals. But they're not your Lord of the Rings elves. No-no, they're hippies!
The game deserves trying before buying. It's linear, that's true. And the moral choice system in OL1 was Evil, or Very Evil (kill the villagers, or merely enslave them). But don't take Yahtzees' word for it alone. Play the demo, THEN make your decision (as you should in any situation).