This trailer was chosen because of its creepiness. The creepiness remains after you watch the trailer. The creepy images and upbeat song may play over and over in your mind after viewing the trailer. I still see that creepy little girl when I close my eyes sometimes. The trailer is memorable and informative. The viewer gets a feel for the game and a preview of the weapons used in the games. Let me know if the song gets trapped in your head.
The producers went in a different direction for the newest edition of Bioshock. Bioshock: Infinite takes place in a different setting from Bioshock. The Bioshock: Infinite trailer still has a catchy tune but lacks the creepiness of the other Bioshock trailers. It can be viewed here.