When Balto wins the race and Steele steps on his foot to make him growl while they judge him, the guy says that they can't trust him. The other guy then says, "See those teeth?" but his mouth did not move at all.
After Balto says "I have the keys to the city", he lifts the bolts out of the door hinges and they fall to the ground, making a metallic noise, like they fell onto cement or something else solid, but there's snow on the ground, not cement or other hard, solid material.
At the end of the movie, after Rosy's father tells Balto that someone wants to see him, we hear lots of cheering and clapping, but we see no people or animals or any other source from which the clapping comes.
After Star says "You crack me up!", he gets bonked on the head by Kaltag. Star then falls down dizzily. Right before he falls down, you hear him say "Whoopee!", but if you look closely, his mouth doesn't move.
When Muk and Luk come after Boris, he uses a bucket and broom to protect himself. But then Luk picks him up from behind and he drops the bucket and broom. When he escapes from Luk's clutches, the broom and bucket have completely disappeared.
As Balto runs alongside Steele to retrieve Rosy's hat during Steele's race, there is a shot from behind the hat where the dogs are approaching the screen. At the rate they are going, they would have reached the hat immediately. However, there is quite some time between this shot and the shot of Balto actually grabbing the hat, indicating that the hat was not as close as it appeared.
When Jenna and Balto are in the boiler room by the boiler, and Steele comes in between them, Jenna's on Steele's right, with Balto on Steele's left. A few shots after Steele says "You start at one end, I start on the other, and when we get to the middle" to Jenna, Balto is not on Steele's left, but by the boiler, almost in front of it.
After Rosy and her father go inside after he says "you're going to catch your death out here", Jenna is in front of the door. After the door shuts, when the camera is looking at her from behind, Jenna is by the big window.
Jenna's position both before and after Balto slides toward her changes. First Balto is sliding toward her right side. In the next shot, Balto and Jenna are touching nose-to-nose, and Jenna is in a different position than in the previous shot.
Near the end of the movie, when Jenna sets the lantern down, there clearly aren't any broken bottles, but in the next shot, there's a pile right in front of her. Also, the lantern appears suddenly on another hill that wasn't there before.
When Star says that they're going in circles, he starts turning around in the lead. Look closely at Nikki's back. There are three stripes. In the next shot, there are only two stripes and the first stripe has turned into two spots. In the following shot, there are three stripes again.
When the shot transitions from the train to the log and then rises to show Steele and the team in the distance, look very closely at Steele's head. His black eye patches are missing. Also, the white stripe is missing from his tail.
While Steele and his team are slipping down the icy hill, there's tons of sticks and trees and lumps of snow, making it nearly impossible to get down. But when Balto looks down the hill at the team, it just shows an icy hill, no branches or trees.
In the race to see which dog is the fastest for the team, Balto joins, but after the starting gun goes off and the dogs start running, Balto is nowhere to be seen in the race when they run by the camera.
In the very beginning of the movie when Steele is racing the other team, a couple shots show that Star's tongue is blue, but a few shots later in the same scene, his tongue is pink, and remains that color for the rest of the movie.
When Steele throws the sausage at Balto to blame him, he makes a Pointer-like motion and raises his left paw. He has four toes on the three paws that are on the ground, but if you look closely, the raised paw has only three toes.
When Balto gets up when he sees Aniu's pawprints in the snow, he puts his right paw in one of the prints a couple times, but each time, there's no print where he lifted his paw from to put it in Aniu's.
In the ice cave, when the dogs are running from the icicles, the medicine crate gets broken. When Balto jumps off an icicle to repair the crate, the crate is intact. It can be seen intact a couple times before he fixes it.
At the end of the movie, when the sled stops, the doctor rushes out, and the lantern is on top of the crate. In the next shot, the crate is being opened, and someone is holding the lantern. Also, no bottles of medicine are missing, even though one fell out and broke in the ice cave. Furthermore, the crate is intact, even though one of the sides was broken just minutes earlier.
At the end of the movie when people are petting Balto, he gets out of the harness (which falls to the ground), then the shot cuts to Boris flying at him. When it cuts back to Balto, there is no sign of the harness.
When Balto is climbing up the mountainside with the crate of medicine, the spacing between Nikki, Kaltag, and Star is different in the wide shot that shows the team. Also, their positions and distance from the edge of the cliff are different in this shot.
When Steele, Nikki, Kaltag, and Star where in the alley antagonizing Balto, Kaltag hits Star on the head, and it shows Star as missing a tooth. When Star gets up and shakes the snow off his head, he says something to annoy Kaltag, and you can plainly see that he is no longer missing the tooth.
Two shots after the man lights the lantern, a shot looking into a building shows Steele and the other dogs by the boiler. Look at Steele. His back legs are flat on the floor and his front legs are crossed. In the next shot, his back legs are off the floor, and he holds his head with one of his front paws.
When Balto and Steele get into a fight, Steele falls off the cliff. As he is falling, you see that the face of the cliff is rocky, with a few snowy patches. But in the shot where Steele has hit the ground and is rolling at the bottom of the cliff, the cliff face is totally snow-covered, with few rocky patches.
After Balto slides toward Jenna, they are touching nose-to-nose. A shot shortly after shows Rosy's dad calling Jenna. When the shot comes back to Jenna, about 3 or 4 seconds later, Balto is now in an alley. There is no way he could've gotten in the alley that quickly.
Jenna is a Red and White Siberian Husky with brown eyes. Red and White (also called copper) Huskies don't have brown eyes. They have amber eyes and blue eyes, but never brown. Also, they have liver-colored points (eye rims, ears, noses, and lips), thus, Jenna's nose shouldn't be black. Additionally, she is missing the "snow nose" and the pink stripe it acquires in cold weather.
At one point in the movie, a bush plane can be seen being used in one of the failed attempts to carry the serum because of the severe weather. Bush planes in the 1920s were not used for deliveries, medicine, or mail. They were used for surveys and firefighting and were popularized after World War II. Before that, they were not a common sight. Also, bush planes were concentrated in Canada and weren't used commercially in Alaska until the 1940s.
In the beginning of the movie, after the team turns a corner and is running down the street, two shots show Balto looking at Jenna off-screen, with the team in the distance. If you look closely, the dog team is just making running motions and not actually moving. At the rate they were going, the team would've reached and passed Balto fairly quickly.
When Balto and Boris are standing on the fence, and Balto is getting ready to race with the other dogs, Boris sits on a windowsill and swallows a soap flake. When he spits it out, his eyes open wide and he doesn't have any pupils.
After Steele says "Well, maybe your taste runs more toward... wolf" to Jenna, she walks away, being called by her owners. Then Dixie walks over to him and makes a suggestive comment. During this whole time, if you look closely, none of the people behind them or in the distance move.
When Balto is talking to Jenna outside the hospital, when he says "Hi. Look, uh... just a shot in the dark, but I was wondering if, uh... I-I don't know, maybe you'd like to go chase a few sticks by moonlight?", you can hear an echo in Balto's voice when he says "chase a few sticks by moonlight".