When Goku is fighting Ginger and Nicky outside of Garlic Jr.'s lair, a significant portion of Goku's hair is sliced off but in the next few shots his hair is back to normal.
Garlic Jr. wants the seven Dragon Balls to wish for immortality. Before he has his minions search for the Balls, he orders them to kill Piccolo at the beginning of the film because he knows it will also kill his arch-nemesis Kami. However, being a former candidate for Earth's guardian, Garlic Jr. should know that had the assassination plan succeeded, the Dragon Balls would have also ceased to exist, and thus he would have inadvertently foiled his own plan.
Ginger, Nicky and Sansho kidnap Gohan when they were simply searching for the Dragon Balls. They should have just taken the Dragon Ball from Gohan's hat.
The figures that are seen rising from the ground after Garlic Jr. is given immortality are never seen or mentioned again.
In the Funimation dub, after Piccolo drags Sansho down to fight him, Piccolo tells him that he's going to "pay through the eyes" for ambushing him earlier. The correct phrase is either "pay through the ass" or "pay through the nose".