Bioshock is a much easier movie to make, seeing as you have underwater city as the setting, while Gears of War is going to rape its own budget if they shoot it where it needs to be shot, which is Siberia. Bioshock is kinda easy to make a movie out of, while if GoW the movie should be a movie version of the first 2 games, GoW3 is likely going to screw up the storyline