Scott Pilgrim vs. the World (2010)

This is perhaps one of the more interesting cases of a reshoot being dictated by test audiences that wound up being used by the original creator. During filming of Scott Pilgrim vs. the World, original graphic novel writer Bryan Lee O'Malley had not yet finished the series and was working hand-in-hand with director Edgar Wright on the film. The two had bounced ideas off each other with each medium influencing the other. This was especially true for the ending, as neither Wright or O'Malley had a solid concept for how to end the story. Initially Scott (Michael Cera) was going to wind up with Knives (Ellen Wong) at the end and that was the first ending shot. Test audiences didn't respond kindly to it, leading to a new ending that saw Scott end up with Ramona (Mary Elizabeth Winstead) and Knives curtly stating that she was too good for him. Audiences responded to this better and it wound up as the final ending for both the film and graphic novel series.