mrkgnao: I haven't played any Zelda games, but the wikipedia definition of metroidvania reads:
"Metroidvania is a subgenre of the action-adventure video game genre... Metroidvania games feature a large interconnected world map the player can explore, but access to parts of the world is limited by doors or other portals that can only be opened after the player has acquired special tools, weapons or abilities within the game. Acquiring such improvements also aids the player in defeating more difficult enemies and locating shortcuts and secret areas, and often includes retracing one's steps across the map."

This description fits Darksiders like a tremor glove.

mrkgnao: I haven't played any Zelda games, but the wikipedia definition of metroidvania reads:

paladin181: Darksiders feels like a dark Zelda with the gadgets and puzzle-like boss fights. Metroid-vania also usually includes a lot of exploration and Darksiders is a little light on that. I'd put Dark Souls in that category before Darksiders. But I can see how it fits there with the way the items work.