Plot hole: During the lesson at school, Goku learned that the eclipse is due to occur "in two weeks' time." The same night he goes to Chi Chi's party and Grandpa gets killed. The day after, he departs with Bulma for Paozu, which is pretty close to where he is (they go by motorbike). But in Paozu, Muten tells them that they have "seven days." (00:10:25 - 00:33:00)
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.
Plot hole: Muten sees Goku perform the technique his Grandpa used, and says "Shadow Crane Strike. I'd recognize that anywhere. How's Gohan?" A few scenes later he goes "Shadow Crane strike is the most basic of all the air-bending techniques." Which is it, Gohan's technique or a generic level 1 airbending spell? (00:30:55 - 00:34:50)