Harmony of Despair marks the third shift in the 2D Castlevania franchise: it mixes the slow single-player burn of exploring a sprawling castle seen in Symphony of the Night (also available on XBLA) with a six-player co-op jaunt through massive levels, as seen in the franchise's previous iterations.
Each level has a 30-minute timer attached, and is only ended by defeating that castle's boss or by dying. And you will die a lot to begin with - despite its platforming trimmings, Harmony of Despair has the soul of a grindcore RPG, and you'll spend a lot of time repeating each level.
Once you've clocked enough playthroughs to upgrade your character's stats and worked out each enemy's attack patterns, the game starts to open up and you'll find yourself enjoying the run-throughs. You can only upgrade in safe rooms dotted throughout each castle or in the main menu, and character stats carry over, so it's great for perfecting runs and posting videos or scores online. The game's repetitive nature is not for everybody, but get a group of dedicated friends on side and you're looking at the ultimate anti-Twilight experience - a vampire tale with real teeth.
Requires work, but rewards those that do