In Tim Avery's final confrontation with Loki, he takes off the mask. In the next shot, he isn't holding it.
The first time Loki looks through the mask's eye holes, nothing is printed on the back. Later, when Loki looks at the back of the mask, "Made in Taiwan" is printed on the back.
When Tim wakes up to feed the baby at night, he smashes the light, but it stays on.
When Tim is searching for his invitation to the party, he says "Now where did I put that invitation?" yet his mouth isn't moving.
During the "Can't Take My Eyes Off You" musical number, when Tim begins wearing the white suit and tie near the end of the song, the shadow of the camera and cameraman are clearly visible on him for a moment.
During the country music rendition of "Can't Take My Eyes Off You", when Tim and the guests start line dancing, several crew members operating a camera can be seen filming the scene to the right.
In one scene, Odin possesses Tim's body and removes Loki's powers, rendering him mortal. However, in the next scene, the baby lifts two garbage dumps and crushes Loki with them, yet somehow he survives this without a scratch.
In the previous film, it is established that the mask only works at night, yet in one scene, Otis is seen wearing the mask during the day.
In the film, Odin tells Loki about the baby born with the powers of the mask, while possessing the body of a man next to Loki, and then tells him that if he finds the baby, he will find the mask. If Odin could find out that there is a baby with the powers of the mask without the help of Loki's presence, how come he cannot know the exact location of the baby, let alone the exact location of the mask.