OXM has conjured up a four-page preview of BioShock 2 after getting a firsthand demonstration of the FPS/RPG-lite sequel.
A less obvious plus is the ability to go outside Rapture, as you can now survive underwater. You can use this to sneak peeks into internal areas (some recognizable from the first game) and harvest Adam-carrying slugs straight from the seabed, but it's also the best way to take a break and just marvel at the wonderland you're playing in. This is the money shot of the demo, trudging through the plant life and marine debris while the sea rumbles and roars around you, the stunning structures of Rapture rising overhead. It's breathtaking.
But the most important part of being a Big Daddy is, of course, your relationship with the Little Sisters. As with the first game, how you deal with them affects your progress but this time you're fighting with, rather than against, them. Having dispatched the first group of Splicers, we go on to rescue a lone Little Sister from Splicers that had slain her protector; in the game it'll be you doing the slaying and then slotting in as the new, slightly blood-streaked father-figure afterward. Little Sisters are so strongly conditioned that they can overlook this, and will willingly hop on your shoulders and go Adam-hunting.