Three names and three reasons why you should be interested in Dishonored: Raf Colantonio, Harvey Smith and Viktor Antonov.
Colantonio is known for his work on Arx Fatalis and Dark Messiah of Might and Magic, Smith is famed for his contributions to Thief: Deadly Shadows and the Deus Ex series, and Antonov is the chap that designed Half Life 2's City 17. So while Dishonored might be a new IP with a stupidly spelt name (where's the 'u' dammit!?), it's got a pedigree that will likely prick up a few ears.
You play a fellow that goes by the name of Corvo. He was the bodyguard to an Empress, but then she went and got herself murdered. The powers that be think it was him that gone and done it. After doing his time, he's released back into the big wide world, and there's one thing on his mind: finding the bastard that set him up. While Corvo is a silent protagonist, it's fair to say that all that time in the slammer has changed him somewhat. Once a respectable bodyguard, Corvo is now an employee of the shadows; an assassin.
His quest for revenge unfolds in the city of Dunwall. Despite the 17th century London vibe and steam punk technologies - cobbled streets juxtaposed with steam boats and dishevelled looking robots - the environment smacks of City 17. The art style is certainly similar, but the similarities are portrayed more in tone than anything else. During an industrial revolution fuelled by the discovery of whale oil, Dunwall has seen great technological advances. Poverty is still rife, however, and there's a great sense of oppression hanging over the city. Guards litter the streets and order is enforced with a heavy hand.
What's worse, half the population has fallen victim to the plague, with rats still scuttling about the streets, spreading their vile diseases. Like the plague, the gamescom demo begins life in the sewers. Our mute hero is given a mission to assassinate a corrupt lawyer, who is scamming the denizens of Dunwall of their hard-earned coin.
As he emerges from the dank underbelly of the city, a tanker sails past along the river, a dead whale hanging from its deck. It's an impressive scene, and a great tone-setter. The whale oil is what fuels the city. One of the first portions of gameplay we see revolves around something called a Wall of Light, which - powered by whale oil - stops rodents (and other street-rats) making their way into the city. Unless you're sporting the correct key of sorts, the gate will electrocute anybody that passes through it. To get the lawyer, Corvo needs to pass through just such an obstacle. Suffice to say, he doesn't have a key.