Continuity mistake: When Nuclear Man arrives on Earth, he enters a shady place which makes him loose his power and cools his body, producing some frozen-like smoke. The next two times that he enters a dark place (inside the elevator and in space) he doesn't produce the smoke. FX budget problems here?
Revealing mistake: When Superman saves the people that Nuclear Man throws up into the air, as they lower you can see the support wires holding them up.
Revealing mistake: When NuclearMan goes to destroy the Great Wall of China, there is a brief glimpse of him wearing support wires.