If you like your RPGs dark and generally gloomy,
The Witcher 2: Assassins of Kings definitely delivers on that. In this dark medieval world, racism runs rampant, sexism is a way of life, and war is an ever-present threat. Geralt, the game's star Witcher, walks a fine line between hero and hated freak.
The story starts out with the perfect crime: another Witcher frames Geralt for the murder of King Foltest. Geralt, having been the King's favored protector up until this point, has to scramble to clear his name. You embark on a quest to find the killer, and of course, help quite a few people on the way.
There's a lot of political stuff about kings and royal lines of successions, Geralt's past, and other background story that you will need to catch up on to fully appreciate every bit of story you find. Honestly, the first game seemed to count on you having read the books as well, so don't worry so much if you hear a bunch of background detail that you don't understand. The basic plotlines and characters are easy enough to understand. Triss is your old flame, Zoltan and Dandelion are your old pals, for example. A big fold-out map also helps with the geography of the wars and political disputes. Basically, if a few names are dropped that you don't recognize, chances are you'll hear more about them if they're truly important to the story.
If you've played the first game on the PC, The Witcher 2 has been simplified quite a bit. The rhythm-based combat system from the first game is gone, replaced by a more standard hack and slash interface. You don't have to find a fire to meditate, and making potions is a lot less experimental (no making self-blinding potions with random ingredients anymore). You also can't get drunk anymore. The leveling tree is also a bit more simplified, with simple talent points instead of points in bronze and silver categories and so on. This doesn't mean The Witcher is simply a linear RPG on rails now, just a bit more streamlined.
The Xbox 360 version of the game also remains faithful to the PC version in the romance options as well. It's pretty darn explicit, and earns the M rating with ease. But if those scenes didn't do it for you, the foul-mouthed citizens of The Witcher's world should. Every other line out of people's mouth is about "ploughing" this or f- that. I mean, everyone, everyone has sex on their mind in this game. Actually, the insults in this game are pretty damn creative and hilarious, but yes, so very dirty.