Just before Manolo begins his first bullfight, his father, Carlos arms him with two swords on his back. However, when Manolo enters the ring and fights the bull, his swords disappear and his father later provides him another sword and prompting him to kill the bull.
As Manolo sings "I Love You Too Much," the Mariachi brothers lift him up to the balcony, but in between shots, Manolo switches from standing on Pepe's sombrero to Pepe's back.
Xibalba's teeth change between triangle- and square-shaped.
After Manolo defeats the boar and General Posada declares he is sending Maria to Spain, a piglet urinates on Manolo's pants, but there is no visible stain of urine on Manolo's pants.
It is never specified why Manolo's father and grandmother appear in the Land of the Forgotten upon dying. If no one alive remembers them, they should take a green dusty form.
Mary Beth says that November 2 is the Day of the Dead which is partly true. The "Day" in fact lasts from October 31 to November 2.