Continuity mistake: Dre visits Han when he is smashing his car, and Han sits in the driver's seat; Dre sees the paper clip on the hood - the paper moves several times during the shots. From having a quite amount of glass on it, to no glass, to a little glass. And it switches positions three times.
Continuity mistake: In the scene where Master Li looks at his students bowing to Mr. Han, he is standing up in the crowd and a few moments later he is on the floor behind Mr. Han and Dre when they do their fist bump. In the alternate ending he was on the floor because he was beaten by Mr. Han in a battle, but in the original scene he just randomly appears on the ground.