Anarchy Reigns is amazing. It's one of the most ridiculously brilliant online multiplayer ever released, hailing from the developers of Bayonetta and God Hand, but SEGA royally screwed the pooch by staggering the release date, leaving the player base fragmented and very sparse. Still, the campaign is fun, the characters are incredible and the game's and a steal at £3.95. I'd love to organise a proper MP sesh on this at some point.
Thanks to Jas10 @ HUKD!