Revealing mistake: In the upstairs bedroom scene after the police and FBI serve the warrant at Niko's home. Sharon Stone is there with the baby. There is a shouting match between Niko and another officer. The Officer yells "take it easy, Steve " or "take it easy, Steven". His line should have been "take it easy, Niko"
Revealing mistake: Near the end when Nico is just about to break Zagon's arm, you can see it's not his real arm because the hand is the wrong color and constantly locked in the same position, never moving.