Strange and wonderful. Those are the two words that best describe the BioShock experience. What other game has dared to throw so many bizarre oddities - killer diving suits, cannibalistic little girls, underwater utopias, gene splicing drugs - together in one package? More importantly, what other game succeeds at being this crazy and, at the same time, this believable?

To fully understand and appreciate BioShock's unique achievement, though, you have to know how it started. How it transformed. How it mutated. In order to chart that evolution from weird to weirder, we scoured the creative team's archives for early art, original sketches and concept paintings. Then we asked a senior artist, Hoagy De La Plante, to make sense of it all. The journey he and the art tell, like the game, is a strange and wonderful one.

GamesRadar: Describe BioShock in its earliest stages. What differences would surprise fans the most?

Hoagy De La Plante, Senior Artist on BioShock: Initially, the Little Sister was just a tiny slug that wandered around the environment - you could gun them down if you wanted to. One version of the Big Daddy was this monster with amputated legs, riding around strapped into an antique wheelchair with cannons hooked on. That never made it past the concept stages for obvious reasons.