Other mistake: When in the cave, Leia falls and is caught by Han. She tells him that "being held by you isn't quite enough to get me excited." As she is saying this you can see Harrison Ford mouthing her exact words. (00:44:05)
Other mistake: When Clark and Lois are on their way to the diner, the wide shot of their car driving along looked very familiar. In fact, it was footage used in the first movie, where the car was used as part of Lex Luthor's "real-estate" plan and was run on remote control. If you look closely in part II, no one is driving the car yet you hear Clark say to Lois, "Hey, you seem pretty quiet over there...."
Other mistake: When Arthur's father takes his ball away (just before Richard Collier signs the register), Richard is looking the other way while Arthur's father puts the ball somewhere behind the counter. Yet, when Richard decides to give Arthur his ball back, he reaches over the counter to the exact place Arthur's father placed it even though Richard never saw where it was placed. (00:54:30 - 00:57:10)
Other mistake: Near the end of the movie, Dave Speed jumps onto Torpedo's private plane and starts steering it to the ground. The plane is white with obvious red stripes. However, Dave Speed is supposed to lose his super powers when he sees red.
Other mistake: After rescuing the boy, Jamie gets the 1946 Ford truck stuck, having rounded vent window frames. But inside as she tries to move the truck we see "dogleg" vent frames from say a 1963 Chevy truck (more pointed, angled back).
Other mistake: When Voltan murders the nun who betrays the group, there are a number of errors in quick succession. First, he appears to stab her in the arm, judging from the position of his body to hers when he stabs her. Second, there is no trace of blood on the dagger when he holds it up a second later. Third, her body seems to have disappeared (or at least moved) when the camera changes to a wider shot a second later. (01:15:19)