Sequels are always risky business, particularly when the original game ticked all the right boxes. Bioshock was one of those rare titles that got almost everything right first time round, delivering a complete experience that could easily have existed singularly. After all, what could a sequel possibly bring to a table already teeming with brilliance? When you consider another iconic first-person shooter like Half-Life, the original raised the bar for the genre, delivering a deeply engrossing world and plot. Valve nailed everything a good game should have such as back-story, intrigue, suspense and action. But to the surprise of many gamers, the sequel took that original template and created something perhaps even more special than the first instalment and that, as always, is a rare thing.