The free-form character building seen in Shock 2 will also make its return here. But where Shock 2 had nanotech-enabled skill upgrades for your futuristic soldier, in BioShock you'll gain "plasmids," which are biological augmentations that function in essentially the same way. Your plasmids will be interchangeable, so you can run with a few powers for a while, then swap some of them out and try others at the next opportunity. Those opportunities will come, at least in part, when you find one of the cheekily named "Plasmi-Quik" machines mounted on Rapture's walls, evidence of the highly capitalistic society which are accompanied by sickeningly cheerful branding that must have been used to sell the plasmid lifestyle to the city's inhabitants before their downfall.

Further into the demo Irrational entered a bar, flipped on the lightswitch, and was immediately shot at by a standing turret gun. Like the shotgun adorned from cans, the turret was equally rudimentary; a desk chair with a machine gun roped to it. Taking cover behind a bar, it was possible to grab a few bottle off the counter to replenish health. A downed register yielded some Adams. Like those objects, almost every item in Bioshock's game world can be inspected or interacted with, adding to the immersion factor. To escape the turrets deadly fire, it was possible to initiate a speed burst implant, sending us flying across the room to an open door, and safety. At the stairway's end some armor piercing shells were found, which were highly effective at taking out the turret gun.