Revealing mistake: In the first confrontation between Superman and the Zod Squad, Superman gets chased out over the water. In the first two shots in this chase, if you look at the bottom right-hand corner of the screen (at least in the letterboxed version) you can see the wake of the boat that they used to make these two pull-back shots. (01:34:40)
Revealing mistake: When Zod lifts the boy's father with the beam of white energy, watch closely when he raises him up past the telephone pole...he 'clips' right through it, or rather the pole clips through him, as if he is transparent.
Revealing mistake: When Zod says to Ursa to "blow them a kiss my dear" to the helicopter that's firing on them watch as the helicopter is indeed a real military helicopter, then when it loses control it's an obvious model and just before it crashes into the house it's a full size helicopter again but is completely different from the first one that was originally shown.
Revealing mistake: When Ursa kicks the astronaut into space, she takes a step back and looks upwards. When this happens you can tell that the film is being shown at double speed. Also, when Clark spins the guy on the chair at the end of the film, he snaps back upright far too quickly.