You should know this: The Darksiders CG trailer embedded above is awesome. "But it's a CG trailer," you say, "it should in no way be used to judge actual gameplay." And you're absolutely right, of course. Then again, we already know the gameplay is pretty solid. But forget all of that right now.
All you really need to know is that this trailer features War – one of the Four Horsemen of the Apocalypse – killing the hell out of a bunch of demons. Oh, and he rides a badass flaming horse. That's it. That's all you need to know.