Revealing mistake: At the climax of the exorcism scene, Christie begins spinning at great speed. That's an impressive supernatural feat already, but the real scary part is that to do, so she also transmorphs into a dummy. (00:52:40)
Continuity mistake: The priest is praying and unknowingly almost exorcises the evil ninja, he is holding his onusa (the stick thingy) with one hand or both hands, and when they both speak Japanese the grip of the left hand differs between angles. (00:50:00)
Continuity mistake: Once Christie is all tied up, the ceremony begins. Miyashima is holding a pipe that faces opposite ways between shots when he holds it with both hands. Still holding it with both hands he brings it to her lips, then in close-up suddenly he holds it with just one hand. (00:49:20)
Revealing mistake: During the movie, the ninja crushes with their bare hands a golf ball (in the opening fight) and a billiard ball (in the fight against Case). Both times the ball is replaced by a shell filled with talcum powder. It's especially conspicuous in the case of the cue ball, because the previous 'stunt' involved slicing one in half and the ball looked nothing like the one she 'pulverizes'. (00:04:00 - 00:38:35)
Continuity mistake: In the opening kick of the billiard fight, Christie's foot touches the Miller time lamp suspended over the pool table, which logically begins to undulate. In the next shot, the lamp is perfectly still and untouched. Similar mistake a minute later at the end of the scene; when she leaves using the window, the lamp is moving but almost comes to a complete halt, only to be back swinging wildly at the cut. (00:38:00 - 00:39:00)
Continuity mistake: The scene where Christie eventually succumbs to the arcade machine begins with her top bearing a huge sweatstain throughout the whole length, but ends with the stain considerably reduced (to be fair, there is no frame of reference to categorically exclude that laser beams emitted from bootleg cabinets possessed by evil ninja demons double as dryers, but we can assume it's not the case). (00:33:15 - 00:35:20)
Continuity mistake: Christie triggers Secord's odd tomato juice fetish, and they have sex. She wakes up and checks out the katana in the wardrobe. The sword floats shaking in different ways depending on the camera angle, and the lighting wildly differs as well. (00:29:00)
Continuity mistake: Christie battled the musclehead molesters and her love interest didn't lift a finger to help. He then abuses his cop powers driving her around without her consent; the boulevard he's driving through changes between shots. (00:25:15)
Continuity mistake: After the aerobics class, Christie tells her friendly cop stalker that coffee is bad for his health. In that particular shot she has a sweaty lock of hair sticking to her neck. In the rest of the scene her bouffant 80s hair is styled differently. (00:22:55)
Continuity mistake: When the cops surround the black ninja 'mortally' wounded and still find a way to get killed, the dangerous ninja is in full sunlight in the first angle, then he's in the shade. (00:10:45)
Continuity mistake: After failing to outrun the patrol car on the dirt road (without attempting to lose it in the tree or anything), the ninja turns around and jumps over it. The younger cop in the passenger seat raises his hand and sticks it out of the window; it's there in two shots, and not in the close-up. (00:06:45)
Revealing mistake: As the ninja starts mowing down people left and right before his victim tries to run him over with the horsepower of a little golf cart, you can see his sword is not actually hitting anybody, even when he's supposed to be stabbing and slashing them. (00:04:00)
Continuity mistake: When the first victim of the ninja arrives at the designated spot for the ambush, he stops the golf cart and in a long shot he reaches for his club. In the closer angle the girl on the cart is in a pose inconsistent with what previously shown, and moments later he asks the bodyguards to help him search the ball, holding the club in a pose that changes at the cut. (00:03:30)
Other mistake: Ron Foster appears in the end credits as "Jiminiz", but his name tag much more logically says "Jimenez." (01:29:50)
Revealing mistake: When Sho Kosugi stabs the Zombie Green Black Ninja in the skull, the victim falls down replaced by a dummy. (01:28:25)
Revealing mistake: During the final earthquake, the camera shakes vigorously but not a single blade of grass or leaf moves in the slightest. (01:27:00)
Revealing mistake: During the fight of the monks that happens on the double squared platform, part of spear gets chopped and flies around the set like it's made of the most flimsy material. (01:21:40)
Revealing mistake: Fight with the possessed monks; Sho Kosugi reluctantly kicks the first one, then he has two in front of him; fighting the leftmost one, he hits him with a great kick, but then his backhand is miles away from connecting. (01:21:15)
Other mistake: If you look at the monks when they're training, there are no twins with a goatee amongst their ranks, but when Sho Kosugi has to fight them because the Black Ninja somehow gained the ability to shoot fireballs that turn evil, you can see that he fights and knocks out the same dude thrice, or at the very least he gets up instantly between shots. Also, they were all together when possessed, but somehow they come at him from different parts of the temple. (00:01:16 - 01:21:05)
Continuity mistake: When Yamada causes Christine to faint and release the evil spirit, her body lies on the floor at an ever-changing angle throughout the scene (her feet are pointing 4 o'clock initially, but when the Black Ninja becomes the Zombie Black Ninja they are at 6, and they are at 8 when Yamada looks at the possessed monks). (01:19:25)
