2K Games has today revealed details of BioShock 2's multiplayer component, including word that it's set before the fall of Rapture and includes an experience point system.

Delving into the fiction of pre-revolt Rapture as a Plasmid test subject for Sinclair Solutions, players will duke it out across in the underwater city in locations including the Kashmir Restaurant and Mercury Suites--fully reworked for the multiplayer experience.

Experience points earned--presumably by smashing faces--unlock more weapons, gene tonics and plasmids with which to customise your character. It's yet unclear whether this will be a persistent system--as in Call of Duty 4--or on a per-play basis.

Behind the multiplayer is Digital Extremes, the Dark Sector creator who helped with the PlayStation 3 port of BioShock and co-developed the first three Unreal Tournament titles.

BioShock 2 is set to arrive on the PC, Xbox 360 and PlayStation 3 this fall.