We pick her up and place her on our shoulders. Then we hold square and a trail of pheromones appears. Following this will lead us to a corpse that the Sister can drain of ADAM, getting us closer to that Incinerate Plasmid. But it isn't going to be that easy.
The moment the Little Sister starts to extract the ADAM, every splicer in the area suddenly springs to action. This is where the gameplay really takes a departure from the first game. Rather than just blast away at the splicers, you have to use your noggin. You can to set up a perimeter of proximity mines, cyclone traps and miniature turrets. Then you can hack nearby security bots to fight on your side, and set security cams to be triggered by enemies. The new remote hacking gun lets you hack things from a distance, so you don't have to leave your Li'l Sis alone. You can even use your new rivet gun to plant small mines around the level. When the splicers do eventually come charging in, we have the upper hand, and they don't get near our precious Little Sister and her sweet ADAM.
These siege scenes are really impressive, both as set-pieces and as a way of letting you use the game's myriad weapons and plasmids in an intelligent, creative way. But someone else is looking out for the Little Sisters, and finds you to be a threat to them - the terrifying Big Sisters. They're viciously fast, can hurl objects with telekinesis, and are a nightmare to kill. We can see why Sophia Lamb uses them as crack troops in her bid to dominate Rapture. Nab too many Little Sisters and these terrifying dopplegangers come after you, nimbly leaping across the environment, clinging onto walls and swooping onto you from above.
Luckily you have a few new tricks up your diving-suit sleeve too. Delta can mix Plasmids. That cyclone trap we mentioned earlier; you can make it even more effective by blasting it with your ice Plasmid. This will not only hurl a splicer or Big Sister into the air and smash them against the ceiling, but freeze them too. Then you're free to wade in and do damage with your drill. The drill is an interesting new weapon: 2K Marin have balanced its awesome power by forcing you to constantly hunt for fuel to drive it, but at the same time, they've introduced a brand new upgrade system for making it even more devastating. Fully upgrade your drill and it becomes a bullet-shield. Slugs ping off it as you charge nearby splicers, and skewer them with one swift blow. Every weapon in the game (and 2K have confirmed there are loads of new ones) has a special 'max upgrade' ability'. Another example we were shown was the Dart gun. Sounds weak, right? Wrong. The Dart gun perforates enemies and literally pins them to the wall.
The hacking mini-game has totally changed too. Whereas before the game would freeze, hacking now takes place in real-time, meaning you're open to attack or being spotted by enemies. The new mini-game sees you stopping a rapidly-swinging dial on green sections of a gauge to hack vending machines or recruit security bots. The faster the dial, the more precious the loot in the safe, or more useful the security features will be. It's a more elegant way of hacking, and less intrusive than the old method.
All these new abilities and tactics can all be used in multi-player too. We played a brand-new game mode called Save the Little Sister. Players are split into two teams; one charged with protecting the Sister, and the other with grabbing her and taking her to a 'vent'. It's basically Capture the Flag, but with a typically imaginative BioShock-style twist.
Things get even more interesting when one player is randomly selected to be a Big Daddy. There is regular death-match and team death- match, but it's this mode that intrigues us the most. The multi-player is even tied into the game's mythology too: it's set during the Atlas/Ryan civil war that kickstarted the events of the first BioShock.