Continuity mistake: During the park battle scene where Cho uses fans to fight the cowboy thug, the cowboy's sunglasses appear and disappear between shots.
Continuity mistake: When Braden is confronted by Cho's mother, she throws a blade at him, which he catches and throws back, sticking it in her shoulder. She uses a blowgun and there are two shots of her with the blade in her shoulder and blood on her clothes from the wound. However, when she misses there is a shot of her using a smoke ball where there is nothing in her shoulder, nor is there any blood on her clothes.
Continuity mistake: Just before Cho kills Braden in the final fight, they use ninja-to (swords), but then suddenly the scene jumps to the swords lying on the ground and Braden using a dagger, which Cho drives into its wielder's belly.
Factual error: Star shuriken, despite common misconception, are not inherently deadly weapons. They were mostly used for distraction, since their lack of a single weighted point makes their attack rather inefficient (although the weapon could be coated with poison). Although it is possible to hit an eye, it is very difficult to hit such a small target or scoring a sufficiently deep wound to penetrate to the brain with a star shuriken.
Deliberate mistake: When Braden confronts Cho on the rooftop, he uses dummies of himself to throw his opponent off-balance. But how could he have brought the bulky dummies onto the roof without being in the first place, or without proper preparation?
Plot hole: To murder Chifano's informant, Braden uses a throwing star. But there is one thing which makes this scene illogical: Braden is evidently not in his civilian suit, but in his ninja costume (the ninja suit's armsleeve is definetly on his arm). But since Chifano and the informant are looking in the same direction when the throwing star hits, and since a ninja costume would make Braden stick out like a sore thumb, it is VERY impropable that he'd escape the scene just like that.
Suggested correction: Throughout the movie Braden (as a ninja) has many instances where someone close up was distracted for only a second, only to look back and see he'd disappeared. This is especially true in the final rooftop fight with Cho. So it would be possible for him to be undetected from a distance in the scene where you're talking about. I also just watched this scene, and Cifano and his men are NOT looking in the direction of the informant but about to enter a vehicle when the star hits. They turn around and see him fall into the fountain. It makes sense that they wouldn't see Braden.
Continuity mistake: The Masked Ninja (Braden) carries a lot of weapons which keep appearing and disappearing whilst he inflitrates Chifano's building; his spear-stick and a throwing axe (both relatively big - and therefore visible - weapons), for example, are both there whenever he needs them.
Continuity mistake: When Dave dies Cho is beside him squatting, but in the next shot he is standing up.
Continuity mistake: During the alley fight scene, the Indian hits Cho over the head with a crate then picks him up with both hands. In the next shot, the Indian suddenly is holding a knife.
Continuity mistake: Just before Cho drop-kicks the van's windshield, the Indian is sticking his head out of the window. In the next shot, the Indian's head is no longer sticking out.
Continuity mistake: The van's windshield gets destroyed when Cho drop kicks it, but a later shot shows that it is still intact. (00:39:20)
Continuity mistake: When Cho jumps onto the roof of the van, the driver changes position from left to right. The shot was mirrored.
Continuity mistake: When Cho catches up to the van by jumping on the roof of a parked car, his pose changes between shots.
Continuity mistake: When Cho chases the van, he grabs on to one of its ladder steps. In the close-up, he's holding on by the ladder bars.
Continuity mistake: As Cho chases one of the thieves up the stairs, another thief grabs his leg. In the close-up, the thief is not grabbing his leg.
Continuity mistake: During the alley fight scene, Cho roundhouse kicks one of the thieves up close. In the next shot, the thief runs up stairs and Cho chases him. They are now far apart.
Visible crew/equipment: When Cathy is being slowly drowned in the hot tub there is a shot were we see Braden's tattooed henchman playing around with his nunchucks and just above his head you can see a clear shadow of the boom mic dip into the shot and is then quickly pulled away again. (01:09:19)
Visible crew/equipment: During the final fight between Cho and Braden on the rooftop, Braden sets off a smoke bomb and disappears, when Cho jumps up the chain link fence in search of him there is some kind of equipment attached to the bottom right of the camera lens. (01:15:47)
Revealing mistake: When Cho is climbing up the building near the end of the film the whole wall shakes each time he presses the claws into the concrete, revealing some kind of substitute was used for the brickwork. (01:07:17)
Continuity mistake: When Cho and his friend confront the thugs at the park, when they talk at the start they are in the open air with nothing overhead but when the fight breaks out they are suddenly underneath the adventure playground without having actually moved. (00:49:45)