The single-player campaign, described above, inevitably remains, although we're not shown much of it at E3. The Challenge Rooms are the focus, and come across as tributes to the elaborate puzzles of Portal, designed to utilise BioShock's strengths in a different way. "The fact is, you can play through the single-player game however you want," says Miller. "You may have used weapons, you may have used a lot of gene tonics and constantly switching them out, and me personally I used the plasmids all the time.
"Challenge Rooms make creative use of all these tool-sets in new and fun ways." They "retain the flavour of Rapture", she says, but they are discrete. "We've kind of been joking around that they're the pulp adventures of Rapture," she says, and to illustrate this we're shown how the levels will presumably be presented to the player - via comic book covers bearing names like Sander Cohen's Chamber of Thrills. To access the contents, you'll download from the PlayStation Store and go straight to them from the main menu.
In the E3 example, a Little Sister (Rapture's lifeforce-harvesting brats are as cute and sinister as ever) is trapped at the top of a Ferris wheel, and you have to save her by sending half a dozen jolts of electricity through the busted control panel to bring her basket to the ground. "In-keeping with the problem-solving nature of the Challenge Rooms, we actually don't give you the most obvious electrical tool in BioShock: there's no electro bolt plasmid anywhere in this level," Miller explains as her colleague explores the on-screen atrium. "So the player's going to have to think very creatively about all the ways they can get electricity in the game and get it over to the control panel."
The first of these is easy - a single round of electric buckshot provided at the spawn-point - but the level quickly pushes the player in other directions. One room is home to an iron safe, but it turns out to be booby-trapped, and electrified trap-bolts rope off the exit. Fortunately there was a telekinesis plasmid pickup on the way in, so the player coolly unhooks the bolts without touching them and redirects them to fry the safe, blasting it open in the process to reveal a crossbow with its own trap-bolt - good enough to put another jolt of electricity through the control panel. This is followed by a bit of light mountaineering, riding an elevator to a balcony and then dropping a level down onto a small platform to collect a static-discharge plasmid. Static discharge is like an electric shield, lashing out with a jolt whenever you're struck in melee combat - and the level inevitably introduces a few splicers - Rapture's warped citizens - to help with that.
There's a few more jolts still to go, but Miller and colleagues end the demo to make way for another developer in 2K's showcase hour. "This is only a portion of the full add-on content," Miller says before she disappears. "We're not speaking about any other portions today but I can tell you they encompass a wide variety of gameplay - from puzzle elements such as we're demonstrating today to the more traditional combat that BioShock is known for.