Visible crew/equipment: In the opening credits sequence, where Chosen One is driving a car and Master Tang as the narrator says "And sometimes he drove," you can see the faint reflection of the camera car filming. It's best to see on the tail of the car and just below the silver bar you can see the wheels of the camera car.
Revealing mistake: When Chosen One is training and Wimp Lo comes up to him and says: "Knock, Knock. Who's there?" You can see that he is transparent because the scenery is visible through him, this is easily seen in his black hair. It is also apparent when he says, "Take a close look 'coz I rule baby". But by the next shot he isn't transparent anymore.
Continuity mistake: When Chosen One is training to defeat Betty by practicing on wooden dummies, there's three shots of him hammering. In the first two the wooden Betty had lots of hair and a mouth, but in the third one, it has a little bit less hair and no mouth.
Revealing mistake: When the Chosen One is fighting Betty in the river, Betty turns around and hits the Chosen One with his claw, sending him flying. In his flight, you can see the Chosen One's face is not a white man, but an oriental man. They have forgotten to paste Steve Oedekerk's face over the original character from the original film.
Revealing mistake: When Chosen One is fighting the masked attacker (who later turns put to be Betty) he claws out their eyes and starts screaming and then his vein in his neck bursts. When this happens though you can see a patch that is bigger than the skin on his neck and it wrinkles it out, revealing to be the blood patch.
Continuity mistake: When Chosen One is going to fight Betty in the lake when he is swinging his chain, Chosen One is stopped by a man who turns out to be Ling's father. In Steve Oederkerk's closeups, the sky is a light blue with some clouds, but in the long shot with Chosen and Ling's dad, the sky is dark with few clouds.
Continuity mistake: When the Chosen One wakes up in the scene where he meets Whoa, his hat is in front of him and about two inches to the left of him. But the next shot of him stretching and waking up his hat is way farther away, so either he, or his hat moved.
Revealing mistake: When Chosen One and Ling are talking and Chosen One says/shouts, "I implore you to reconsider", look at his head as the camera zooms in. After the zoom stops, you can see that Chosen One's head "grows" for about a half-second, the result of a flub-up of the special effects. (His face is pasted onto another actor's body.).
Revealing mistake: During the scene where Betty is at the table with the Chosen One, when the camera is behind the Chosen One, you can see a mustache on him sticking out on the side. The Chosen One does not have a mustache. This also happens when Betty is performing his skill. This is where Steve Oedekerk is replacing Master Tang instead of the Chinese guy he usually does.
Continuity mistake: When Chosen sees all his friends wounded in the field, he has a tattoo saying "mouth" with an arrow on his left cheek. The tattoo can't be seen after this scene. There was a deleted scene where Chosen One was captured and tortured, one of the tortures was to tattoo an arrow that said 'mouth' on it. In another one, the "one boob" woman uses magic to erase it. Still a mistake, but there's the reason.
Continuity mistake: When the Chosen One is meeting with Master Tang, in the first shot you see that Master Tang is sitting down. However when Chosen One says "and that day, I vowed to find the man who killed my family", you see Master Tang walks past the Chosen One.