The first Bioshock game was always going to be a tough act to follow. A critical and commercial hit, the BAFTA award-winning 2007 original blended an unusually literate science-fiction plot (which referenced, among other things, the work of Russian philosopher Ayn Rand) with a refreshingly intelligent take on first-person shooter and survival horror gameplay styles. Not only that, but the whole thing was topped off by some highly distinctive Art Deco visuals and a mournfully atmospheric sound design.

Thankfully, Bioshock 2 manages to avoid the fate of many other sequels, exceeding expectation to match or improve upon its predecessor in almost every way.

Once again, the action takes place in Rapture, a vast city built beneath the sea by Andrew Ryan, an idealistic philanthropist with a vision for an underwater Utopia, free from the tyrannies of religion, politics and censorship. At some point before the events of either game, however, a combination of cabin fever and genetic drug abuse appears to have sent Rapture's population into meltdown. By the time you begin playing, most inhabitants have devolved into narcotic-crazed mutant loons known as Splicers and Rapture itself lies in ruins. Only a few unaffected survivors are left skulking around the city's leaky, barnacle-encrusted corridors. Some of Rapture’s citizens will attempt to help you but the majority are out to stop you at all costs.

Bioshock 2 is set 10 years after the first instalment and this time around you play a prototype Big Daddy, which were one of the most fearsome foes in the previous game. While you don't necessarily need to have played the first game to enjoy Bioshock 2, it helps to appreciate some aspects of the story if you’ve already had experience of being on the other side.

Bioshock 2 is as a shooter that allows you to wield two weapons at a time, a series of traditional projectile weapons (rifles, shotguns and so on) in your right hand, and a range of ingenious genetically-enhanced powers (called plasmids) in the left. You can freeze an enemy into a block of ice with a zap from your left hand before shattering them into a hundred pieces with a grenade from a launcher in your right. As a Big Daddy you also get to fend off aggressors with your deadly drill attack, should they get too close.

Levels take place in various areas of Rapture, which you unlock as you progress. Each one is different and, while the game's main objectives lie along a relatively linear path, you are essentially free to explore each level as you wish. Doing so reveals some useful secrets and upgrades.

Every area also contains a number of Little Sisters, which you can hunt down and adopt, though you'll need to defeat their existing guardians before you can do so. With a Little Sister at your side it's possible to search for something called Adam, a substance that acts as a currency for the genetic upgrades available in the game. Added to the mix is a new type of baddie: the Big Sister. Much more agile than the lumbering Daddies, encounters with Big Sis are rare but deadly.

Just occasionally, Bioshock 2 manages to go one better than its forebear. The game does a much better job of encouraging you to improvise and develop your own combat strategies, for example, while the various mini games (such as when hacking a security device or a vending machine) are more streamlined than before. In addition, there's now a selection of highly enjoyable multiplayer modes, including some imaginative Bioshock-themed variations on old favourites, such as capture the flag.

However, Bioshock 2 offers no true equivalent to the feeling of awe that the first game inspired. This time around, the setting isn't quite as mysterious, the moral choices presented throughout aren't quite as unsettling and the backstory isn't quite as absorbing. In all other respects, however, Bioshock 2 is an extremely worthy successor to one of the best games of the decade. It's also worth mentioning that Bioshock 2 is frequently every bit as gory and terrifying as its 18 certificate would suggest – as such it won't be to everyone's tastes.