Hey why does the GameInformer for Bioshock not match up with the game itself?

Hey I just found my old copy of GameInformer for Bioshock, was looking in it and relized something funny and strange. The Big Daddys do not match in the game and magazine. The big daddys in the magazine are weird looking and have funky guns. The only 2 i know are the Rosie and Bouncer (and the Elite versions of course) in the game. i have never seen any like in the magazine, but anyways i was just really wondering because i remember i was really looking forward to those guys plus in the magazine it shows you with some cool looking gun like the big daddy has but when i played i never got that gun. why does this stuff not match up please tell me i am very wanting to know because i'm looking forward to Bioshock 2 but i don't want the GameInformer totally different than the real game. please tell me why that is. I really want to know please tell me if you know anything at all about that!!!!!!!!!