Factual error: The bat signal at the end of the film defies physics. The spotlight is a few feet across and is projecting the signal onto clouds far above. To do this, the light beam should get wider as it climbs up (like a flashlight's beam aimed at the ceiling). Yet the shot of the clouds shows rays of light getting wider as they go downward, like sun rays through the clouds. For this to exist, there's either a bat signal floating far above and through the clouds, or the one on the roof needs to be several miles wide, focusing a beam that narrows as it climbs.
Factual error: When Rachel is driving to Arkham Asylum, traffic is moving in both directions, but the three lanes of the road are separated by identical white dashed lines indicating a single direction. In the US, 3-lane traffic (2 lanes one way, 1 the other) have the single lane bounded by a solid yellow line, with yellow dashes if you can pass, or a second solid yellow line if not.