Continuity mistake: The police arrives at the house under construction with three patrol cars. Watch as the cops get out of the cars and take position; their positions do change between shots - for instance, one cop stands behind the open passenger door of the car in front of him, and in the next shot he's still running towards it, and the guy behind the driver seat-side door of the other car points the gun with both hands first, then just one. (01:10:55)
Revealing mistake: When Christine escapes from the window, she turns into an athletic guy. (01:10:45)
Continuity mistake: When the Black Ninja has been unmasked, somehow both warriors get scared by the cop sirens. Christie escapes through a window; in the first shot the window is half-opened, in the second, all of a sudden all she has to do is push the fly screen, as the window frame has been removed. (01:10:35)
Continuity mistake: When the Black Ninja drops a large wooden board on Yamada, Sho Kosugi's hands are positioned differently between shots, and when he breaks it, the two large pieces end up in different spots depending on the camera angle, even few seconds when the Black Ninja keeps going Donkey Kong on their opponent throwing more garbage at him. (01:09:35)
Visible crew/equipment: Inside the house under construction, the Black Ninja drops a bunch of dirt from the top of the stairs (an action she will repeat later). The rubbish hits the camera that shifts slightly towards the end of the shot. (01:08:50)
Continuity mistake: When Sho Kosugi breaks some boards that block the entrance to the house, the leftmost board is just chipped in close-up and fully broken in the following shot. (01:08:25)
Continuity mistake: In the opening phases of the fight between the two ninjas, the one possessing Christie tries to stab Yamada through a window. In close-up, Sho Kosugi has both hands on the brick sill, but in the next shot his left hand is still distant and closer to the doorframe. (01:08:20)
Continuity mistake: When Christie kicks a cop head-first into a gravestone shattering it (the gravestone, not the head, although one wonders how just the latter could happen), the stone breaks in two completely different ways in separate shots. (01:06:55)
Continuity mistake: When the ninja parries the baton strike from the guy making all the swooshing noise, her right side of the body (and her arm, specifically) are already prepared to hit the second guy while the left hand brings down the baton. The next shot though opens with her right arm low and her left arm high over her head. (01:06:45)
Continuity mistake: When the patrol car chases the ninja at the funeral shooting at her with a shotgun, there's a POV shot from the driver, who has his right hand at 12 o'clock on the wheel. Reverse angle and the hand is gone. It happens again moments later when the driver stops the car, and at the cut it switches from 10 to 2 o'clock with opposite hands. (01:05:50)
Revealing mistake: In the sequence with the ninja knocking two policemen off their bikes at the funeral, the one on the right goes down (not to dodge, but acting like he's being hit) a second before her foot actually hits. (01:05:40)
Revealing mistake: At the funeral, Ninja Christie shoots two arrows. She prepares to shoot a third, but meanwhile (in the shot where a widow is looking around worried and a man in a light suit pulls her away) another guy just dies for no reason hit by something invisible. (01:05:10)
Continuity mistake: At the funeral, Ninja Christie shoots one arrow, then a second. The officer dies holding one hand to his chest in the shot, both in the next. (01:05:05)
Continuity mistake: When Yamada stops the hearse, the shadow of the vehicle doubles in size between shots. (00:57:10)
Continuity mistake: When Yamada knocks out the group of three guards he failed to sneak past at the morgue, the guard to the left goes down dropping the nightstick at distance and at a certain angle. Yamada walks past them and the baton is closer and at a different angle. (00:55:55)
Revealing mistake: The first time we see the legendary Sho Kosugi properly in action, he knocks out a guard, then he throws a shuriken at another and fights him. He dodges his baton, kicks him, and then you can see clear as day the awkward moment when the stuntman just stops and waits for the follow-up push-kick towards the dumpster. (00:55:20)
Continuity mistake: When the priest tries to read from a scroll and gets laughed off by the ninja demon, he is holding the scroll in a different way between shots - just use the little string as reference. (00:51:10)
Continuity mistake: When Billy pays the wise man from the Orient, the wad of bills does a 180° between shots. (00:47:45)
Other mistake: This is just baffling; in the scene where Christie is wearing a rather sweat-stained pink top and Billy turns the music off asking her "Where have you been?" they are the only ones in the room, but someone out of frame throws what appears to be a puppet on Christie bed (!?). (00:45:45)
Audio problem: When Christie moves on to the second girl in the hot tub to strangle her, she screams "N-noooo!" but her lips and facial muscles don't move. (00:44:20)
