Deliberate mistake: When Spidey jumps on the hood of the truck, Rhino squirts him using the wipers. Funny, but he can do that only because the detergent sprays forward instead of the angle actual windscreen washers are pointed at. (00:12:50)
Deliberate mistake: Conan Stevens' character in this film is an unnamed orc who briefly attacks Gandalf and is defeated by Galadriel. However, in the first movie, the same character briefly appears in the flashback to Moria and is credited as "Bolg." This is due to the role of Bolg being recast and the two remaining filmed scenes of the original actor being repurposed. The filmmakers originally intended for first film Bolg to be a younger Bolg, but later retconned this, despite already crediting him as Bolg.