Continuity mistake: Bulma is browsing in search for Roshi, while Goku eats a massive piece of meat. Right at the first cut, the extras that were walking around have completely disappeared, and throughout the scene, cars in the background never carry over from the previous time they were in frame, they just vanish between shots. (00:27:10 - 00:27:45)
Plot hole: Bulma tells Goku about "the little machine I invented. This can detect and locate the signature wavelengths emitted by the Dragonballs." Literally a minute earlier she was not aware of the existence of other dragonballs (which she called by another name she never uses again). She does not live far, since the theft happened only a few hours before, so if she believed already that other "Prometheus spheres" existed, how would she have never detected Gohan's sphere so close nearby when she built that radar of hers? Unless her radar has a ridiculously short range, and then it wouldn't be useful at all during the rest of the movie either.
Continuity mistake: Muten wakes up and he hits Goku, sending him against the wall. Some slips of paper begin falling from the desk, but the quick cut to Chow Yun-Fat's face stops that from happening, everything that was falling off is perfectly still. (00:29:30)
Other mistake: When Goku meets Bulma for the first time, he asks her "Are you Piccolo?" Gohan said that "he's returned", and since Goku knows the whole story about Nameccians, he obviously also heard the story about Piccolo tons of times. There's no possible reason why he'd mistake a girl with a gun for the powerful male-looking sorcerer mentioned by his grandfather (it'd be also pretty surprising if his Grandpa talked to him about the alien race thing but neglected to mention that they are green-skinned and distinctly non-human looking). (00:23:45)
Other mistake: Piccolo kills Gohan using a Vader-esque power to choke the opponent, and crushes the wooden part of his house on top of him (a very large part, some mistake it with the whole house) with a display of great telekinesis that takes him seemingly no effort. Throughout the movie, he never shows this kind of power and control over objects or people ever again.
Other mistake: Fuller's car "explodes" collapsing for no reason, it has been hit with a couple lead pipe swings by a creepily old teenager, never by Goku. And if Goku did it with his Ki, then he'd already have mad power levels, contradicting the rest of the movie. Even throwaway jokes (I would imagine this was supposed to be one) should at least attempt to make sense, or "not not make sense." (00:17:05)
Revealing mistake: The movie shows in Matrix-esque slo-mo the double baton swing Goku dodges, from Fuller and his goon. They are nowhere near hitting each other, and yet, this missed baseball-bat swing causes them to KO each other in close-up. (00:16:55)
Continuity mistake: Chi Chi sends a sad look back to the bullied Goku; you can see she is almost at the entrance, with other students turning the corner. In the following close-up of Goku, the cool kids (as much as people in the 27-32 range can be considered 'kids') have moved backwards and have still a way to go before entering. (00:07:30)
Continuity mistake: When Goku calls Fuller's name for "whacking my bike", extras are recycled, appearing both behind Goku and the bullies (super-easy to spot a girl in pink and teal, with her buddy wearing a blue varsity jacket). (00:06:50)
Continuity mistake: After sparring and faceplanting into fruit, Goku follows Grandpa to his little zen garden. There was an establishing shot of the area by the training spot, shown once Gohan jumped on the ropes, and while the rocks and some gravel were visible, the little cement bed and greenery are brand new. (00:02:35 - 00:04:10)
Continuity mistake: At the beginning of the sparring between Goku and his Grandpa, the clotheslines project clear shadows on the ground. During several shots during the silly fight (several from above when they flip around, or for instance the wide shot that follows the bug-eating bit) there's a total lack of shadows. (00:02:30 - 00:03:30)
Other mistake: The history in the world of this movie does not have to follow our own (after all, in Toriyama's creations we have dinosaurs roaming the Earth, and talking animals), however the opening narration talks about how "thousands of years ago" Piccolo bringing our "peaceful planet" and "the HUMAN RACE, on the BRINK OF ANNIHILATION." The movie is set in 2010-ish (Goku has a poster of the "Pazu United" football team, year 2010), and turns out from later dialogue that Piccolo is coming back after 2,000 years. The implausibility of a nearly world-ending global catastrophe happening barely 2,000 years ago and being completely erased from history (nobody remembers Piccolo and everybody laughs off the notion of an invasion around that time) is astonishing, but even admitting that, the opening crawl briefly shows warriors in full plate armor, definitely out of place for circa the first century AD. Everything about the narration leads to a very far back mythical pre-historic past, so when later it turns out it's" just" 2,000 years ago, it makes no sense.
Continuity mistake: When Goku finds his Grandpa covered in rubble, he removes a wood plank; Gohan's hand is on top of the wood at first, then more logically it is under it. Also, when Goku brings him to the dry landscape, he's clean from the dust. (00:20:00)
Continuity mistake: After battling it out a bit, Goku asks Bulma "What happened to your dragonball?" The characters stand still but the shadows have dramatically moved; Bulma's face is fully lit and Goku 's shadow has moved. (00:24:55)
Continuity mistake: During the Mai vs Chi Chi fight at the Toisan tournament, many different takes have been edited together, since the referees appear in semi-random positions on either side of the fighters. (00:49:20)
Continuity mistake: Mai walks into the ruined village. She points a gun at a harmless basket, weapon in her left hand. Change of angle, and she is now pointing the gun with her right arm before walking away. (00:09:05)
Continuity mistake: Mai puts the blood sample in the vial holding the blade with the thumbpad underneath the metal in the closeup, on the external part in the shots before and after. (00:49:55)
Other mistake: Goku turns into Oozaru, and his uniform opens up. Goku reverts to his normal self.and he is also nicely tied back up, sash back in its place, undershirt, etc. Instantly. (01:06:00 - 01:09:00)
