Steals most of it's good ideas, but uses them very well indeed.
It may take a while to come to this conclusion however, because on first play there seems to be little to Darksiders to set it apart from other games in it's genre. At first you'll be forgiven for thinking that the game is rather linear, because it's first chapter is like an adventure on rails, so restricted and obvious is your progress. The graphics, while pleasingly stylised, seem to be low in polygon count and lacking in the detailed textures of other games using the Unreal engine. A particular black spot is the degree of screen tearing...present in the XBox 360 version to a degree that really shouldn't be allowed in any release this far along in a console lifespan. While it is not gamebreaking, it is frequent and jarring enough to take the sheen off what is otherwise a pretty, if unspectacular graphical package.
At times Darksiders can feel like some sort of Frankensteins monster, stitched together from the limbs of it's forerunners. Combat is strictly God of War, with similar weapons, combos and upgrade system, plus you'll be looking for the same chests, and collect souls of different colours. Exploration, dungeons, special items and bosses are Zelda-esque, with a bit of Portal thrown in for good measure.
So, on paper it should really be hard to recommend, but given a bit of time, you realise that these are good ingredients that Darksiders is working with, and the designers are obviously passionate fans of the games that they pilfer from. This is because the copied game mechanics are implemented remarkably well. Combat is meaty and satisfying, with all but the weakest of demons putting up a good fight. As your repertoire of moves increases you can develop effective strategies against the different forms of beasties, and clearing a screen of nasties is never short of fun.
Dungeon puzzles can be the normal mundane switch pulling and block moving, but later in the game, as you have more tools to work with, the puzzles are very clever indeed. Later voidwalker puzzles in particular giving that rare (outside of zelda games), real twinge of smug satisfaction when you figure them out.
More frequent in the later half of the game are the sheer wow moments also. From riding Ruin along a giant worm to successfully facing off against Straga, the boss fights present the most stunning moments, but the more game you uncover them more that the graphical style revels itself to be more than a pastiche of World of Warcraft and become it's own beast. Lonely but deadly deserts, a submerged town, broken and decayed highways or ruins of a long-lost garden are beautiful in style, even if not pushing the XBox like Gears of War or Modern Warfare. It is nice in particular to have a varied palate in a game, from decay through to blue skies, instead of endless greys and Browns (I'm looking at you Gears & Fallout...)
The feeling of progression in terms of power of War, and his abilities is satisfying, and you can't help but love Ruin, who is gorgeously animated and useful, if slightly underused.
On finishing the game, instead of thinking of the game as a melting pot of others, it's hard not to appreciate Darksiders as it's own whole. More than that, the sense of disappointment at completing the game speaks volumes of it's quality. The ending hints so strongly of a sequel, and tantalises with ideas of what it could contain, that I can't wait to see what lies in store for War and hopefully his three brothers.
To those who haven't experienced his first adventure though, I would heartily recommend it.