At the start of the episode, the Specter Speeder should have been able to phase through the ice cliffs due to the ghostly properties of real world things in the Ghost Zone; they make this mistake too often.
When The Specter Speeder and Danny landed in the snow, Danny is first seen without any snow on his head, but in the next frame he suddenly does.
When the other monks join Danny and surround Vlad, the one who speaks is holding a spear, but in the close up he is holding a sword like everyone else.
For the beginning portion of the episode, Danny's hair style is exactly like Timmy's hair style (as in missing the top spike). This is eventually corrected in later scenes.
In Salem, Massachusetts, Tucker yanks Danny out of the blood blossom circle, but when he finishes eating the flowers, Danny is shown back inside of the circle.
Because of the title card, fans at first believed that Frostbite was a villain instead of an ally of Danny.
At one point of her public concert, Ember's black line of makeup under her left eye disappears, but re-appears later.
Between the black out where the commercials would come in Danny and Jack switch places in the boat.
When the scene changes from Skulker crushing the picture of Ember to Ember, Spectra, Kitty looking at Bertrand, Bertrand is seen with white sleeves but it then changes to his usual black coat.
Sam somehow knows Kitty's spell is reversible for only 12 hours, even though she was never told that by Kitty or anyone else.
The setting where Danny and Jack fish changes drastically. Before Skulker's attack, they are at a small spooky, foggy pond in the middle of the night. After Skulker enters, it changes to an enormous lake with a much less spooky setting and is much lighter. It changes back to the spooky setting for a brief time later on.
At one point, when Maddie is talking about her new invention, a part of her belt disappears.
After the ability to transform, the second power Danny loses control over is intangibility. Yet, later in the episode, he is seen phasing through the ceiling to confront Amorpho while the latter is disguised in Lancer's body.
When Danny's parents enter Casper High (Literally destroying an entrance), they say "Freeze Fenton!" instead of "Freeze Phantom." It isn't clear whether they were talking to Sam disguised as Danny Fenton or Danny Phantom.
Throughout the entirety of the episode, Amorpho's true form has no facial features, but on the title card he is shown to have ears without ear holes.
When Amorpho morphs into Danny, as he gets the chest/arm/etc. features, his Phantom arms are out to the sides. Yet in the zoom-out, his arms suddenly drop down.
Early on in the episode Jazz is asleep on her bed, yet when she wakes up she is at her desk.
While checking the security camera tapes in the Ops Center, in one of the frames, Danny's left glove is outlined in black while his right is outlined in gray.
While Sam was asleep, she was missing her leggings.
When Danny crashes into the table in Sam's dream we can see that a plate also fell, but before that there was no plate on the table.
When the two Sleepwalkers grab Tucker into the air after he jams the radio signal, if you look closely, for a split second the one to the right has light pink eyes instead of the usual red. After they lift him up, its eye color reverts to red.
At the beginning of the episode, Ms. Tetslaff claims that the school day ends at 3:00 pm, but in "Livin' Large," Tucker says that the school day ends at 3:30.
In the flashback/montage where Walker talks about capturing the kids who found the search party, it shows Paulina getting captured and Star running away, when really it was Star who was captured and Paulina got away.
When Danny phases through the cage after setting it down in the grass, a small discoloration makes it appear as though Wulf is not wearing pants.
The original Technus, Technus 2.0 and Skulktech 9.9 can all be seen on the machine.
The Lunch Lady Ghost can be seen both in her lunch lady uniform and in her meat monster form.
Bertrand can be seen in both his Bert Rand form and monstrous Bert Rand form while circling Danny after being released from his net.
Several ghosts appear in this episode, despite having been previously destroyed: Terminatra, Nightmerica, Femalien, Scarlet Samurai, Crystal Leviathan, Empress She-Wolf, Pariah Dark, and one of Vlad's failed clones of Danny. One of Danny's clones is even seen twice in the same frame.
Spectra is shown wearing her red jacket and skirt when she's in the Ghost Zone but is wearing her black suit with green flames when she helps to power the machine.
In the small shot of Dani Phantom getting ready, both of her gloves are white when one should be black.
Freakshow cameos during this scene, despite him being human.
Wulf, captured in Danny's net, is shown with his collar on. However, it was removed before this episode.
The number of ghosts returning to the Ghost Zone after the Earth was saved looked as if it was only several tens of ghosts, though there were possibly hundreds or thousands that powered the machine.
The size of the Disasteroid appears smaller than it really is right before it passes through the Earth. On Tucker's scanners, the TV, and in space, it appears to be about as large as the planet itself, yet as it passes through Earth it appears to be only the size of a mountain.
The storyline indicates that all of the ghosts doing cameos in this episode were Danny's enemies. However, many of Danny's allies, such as Frostbite, Pandora, Clockwork, Wulf, and even Dani made cameos. This could have just been a reason to have all the characters appear in the episode, given that it was the series finale.