In the scene when Fox is walking with Wesley, right before the train surfing scene, she has her hair down and flowy. Then in the next shot, her hair is in a ponytail.
In the office at the end of the film a nameplate is visible on one of the cubicle walls. The nameplate reads "J.G Millar" which is a composite of writer Mark Millar and artist J.G. Jones, on whose comic the film is based.