One of the best games yet.
First of all, lets tackle the menu. The camera circles around your tower in real time. But it's YOUR tower. Throughout the game, you upgrade your tower. It starts destroyed, but you can get items to repair it, make it look cooler, upgrade it, and so on. And the 3d background in the menu shows your tower as it is. Why do I stress this so much? Well, because hitting Continue Game sends the camera into your tower and centers on your guy. Not only does this look snazzy, but you get to play INSTANTLY, without a load or even a black screen. These are the small - but awesome - features you can expect to find all over Overlord.
Other small things that are awesome include the amount of things to do in your tower. There's TONS. You can change it, do "mini-games" (Like going into your dungeon and fighting any enemy in the game you have already fought).
Then the voice acting. It's great. And there's A LOT of dialogue. You also get labels. For example, if you kill all of the humans in the human town of Spree - which you can do and is fun, almost in a GTA type way - you gain the label of Supressor of Spree. Then whenever your in your town, your cheery little jester will run at you yelling "hail the supressor of spree!" and other titles you may have. Of course, if you don't like hearing him, you can always kick him in the face, and he's quick to be quiet.
Enough of the small features though, though they are a big reason why this game is so great. The graphics are just as fantastic as the audio. The game looks amazing. It has a unique style too. It's not exactly cartoony, and it's not exactly real, but it's not really a cross either. It looks quite realistic (which I admire since I despite cartoon looking games), but with a hint of unique cartoonyness, but more in a way that pokes fun at fantasy games, which this game does a lot of. Style aside, this game does look fantastic, in every area. From vast open farm fields, to inside half-ling houses, to dungeons, and to elven forests, the game looks superb in every area.
As for the gameplay, well, you control an arsenal of minions. A LOT of them. You move them the same as you move your character, by "sweeping" them with your right analogue stick. One complaint is that this makes camera use difficult, but it's not bad at all. It will rarely effect you, especially because you can use the left bumper to center the camera the way your guy is looking.
You can also change the view to be over-head, which looks sort of like diablo. Both look fantastic and are fun to use.
The one complaint about gameplay is that you feel a bit underwhelming as the overlord. While the game is about using your minions, it would be nice if you could be more powerful yourself - though, you can upgrade your overlord in many ways, like armor, weapons, and spell. This is a very minor complaint. There's also multiplayer, though I have yet to try that. This, coupled with the fact that the game is fairly long, and has many different ways to play (as in the slogan, you can be evil or very evil), it will have a fair amount of longevity, and I see it as one of those games you come back to replay 20 years later, trying to get that nostalgia.
There it is folks. Overlord is one of the best games on the 360 yet, and one of the best games ever, in my opinion, which I consider fairly credible after many years of gaming. This is a game you should not miss out on.