Gwen wasn't wearing stockings when she was tracking Alan.
When Alan tries to become an alien in the ice building, his Plumber Badge is seen on his chest for a split second although Sheriff Mason took his Plumber Badge. But when he reverts to his human form, the Plumber Badge is gone.
When Alan breaks out of the cell he has his Plumber Badge on his chest, but it was sitting on the desk where Officer Wells was sleeping.
When Gwen tells Ben and Kevin about the hole in the ice building, her stockings are missing for one scene.
When Humungousaur stops Hugo from being pulled into the vortex, he grabs his leg. In the next shot, he is seen holding him by the lab coat, and in the shot after that he is holding his leg again.
When Paradox meets the elderly Hugo, he says he hadn't seen Hugo in 100,000 years, even though he saw Hugo mere minutes ago.
When Kevin finds the new version of his car, he says that it was 'factory new from 30 years ago' and the note from Paradox said his car would explode if it came into contact with anything from 1976. This means that the car was made in 1976 and that the episode takes place in 2006; however, Ultimate Alien and Omniverse is confirmed to take place in 2012 (meaning Alien Force really takes place in 2011).
Ben states that neither him or Gwen know how to drive, although in Paradox, he states that Max taught him how to.
On the first image Gwen is shown too tall and far from Ben and Kevin. In the same scene, Ben and Kevin were looking at Gwen.
In the next image Gwen is closer to Ben and Kevin, but the cuffs on her sleeves are blue instead of white. Also, in the same scene, Ben was drawn at a different angle, Gwen's pose was slightly changed, and all three of them were looking at Manny and Helen as if facing them.
Big Chill is seen pushing the order button at the Burger Shack multiple times. The waitress comes out soon with his order, before being scared away. However, Big Chill never spoke into the speaker, and only pushed the button.
When Big Chill turns away from the metal Burger Shack mascot's statue before flying away, the mascot is no longer visible (even though at the angle shown, it should have been).
When Big Chill was leaving after drinking the molten metal, his Omnitrix symbol was sideways.
When Big Chill drinks the molten metal his teeth do not separate but the liquid gushes in rapidly.
Brainstorm's vomit originally had the color of his brain.
Brainstorm vomits on Azmuth, but in the next scene, Azmuth is no longer covered in vomit.
At the end of the episode, after the Omnitrix reboot, Ben said "Aw man, I don't recognize any of these guys!", making it sound like he had unlocked a whole new set of aliens. However, he only had unlocked Lodestar. Also, no holograms were shown, so Ben wouldn't see any aliens.
When the boys activated the Omnitrix's transformation into Swampfire, they simply tapped the faceplate rather than pressing it down. Ben was shown to attempt this in previous episodes, yet nothing worked.
When Swampfire attacked the Vulpimancers, the leader didn't have its back stripes.
For a second, the Null Guardian's saliva is blue instead of green.
When Sunder jumps at Ben, part of his hair disappears.
When Ben dodges Sunder, his shoulder stripe is on the wrong shoulder.
When Gwen and Julie come to hug Ben, Julie's the same height as Ben and Gwen.
When Ben woke up, he didn't have the 10 on his jacket.
After Seedling 2 reported in, Seedling 3 (via Max) reported to the Highbreed that five Seedlings were present. However, when Max had shown up, four other Seedlings were already present and Seedling 2 did not show up until after Seedling 3 did, meaning that there were six Seedlings and not five.
When Zs'Skayr turned the residents of Vilgaxia into Ectonurites, they had the same appearance of the sun-shielded Ghostfreak from the first season of the original series. However, the Ghostfreak minions were harmed by light, even though they wore the same suit that rendered Zs'Skayr immune to light in the original series.
When Ben sends Vilgax to Zs'Skayr as a distraction, while Zs'Skayr is looking off of the balcony, his eye is green, but when he turns around and replies to Vilgax, his eye is purple.
When Humungousaur falls on Kevin's car at one time while battling the Naljian Destructor as Robot Gwen, it shoots mana which hits the car in multiple areas and all its surroundings, but when the Vreedle Brothers land, the car is in perfect shape and there is only one mana disc stuck to it.
When Pierce was fighting Goop, he broke a single shoulder spike off and threw it but when he threw it and it went through Goop it showed that he broke off two.
When Goop made the tower collapse, Pierce's eyebrow was white.
When Manny fires his blasters at Ben and Ben kicks them away only one blaster falls to the ground but both Manny's hands are empty, also Ben comments that Manny no longer has his blasters despite Manny still having two others in his lower arm holsters.
Somehow Helen knew Manny fought Rath, even though she wasn't around when the fight happened.
When Humungousaur chases Pierce, he smashes the airlock ledge that Pierce leaps over which dents and cracks the ledge. However, in the next scene, the ledge is shown to be intact.
Alan, Pierce and Helen gave their badges for the self-destruct of the ship, but when Pierce is placing the last one, Alan's badge is still on his chest.
The trajectory of the satellite shown on the monitor would not have it crash anywhere near London.
When Gwen tries to remove Ben's shackle, Ben's arm is next to his body on the next shot.
The shackle on Ben's wrist keeps disappearing.
Kevin is shown to be wearing his seat belt when he crashed and even just before Albedo pulled him out of the car. But when Albedo does pull him (and throw him) out of the car, there is no resistance (not even a stretch) from the seat belt.
After Diamondhead shoots Kevin in the back with diamond shards, he has the others in his back, then, after he charges Albedo with a crushed up car, the other shards are not there, nor are there any holes from them.
When Albedo is going after Max, Spidermonkey comes in through the roof of the Rust Bucket, but when he turns into Rath and busts through the side, the hole on the roof is no longer there.
When Albedo was about to turn into Humungousaur, the Ultimatrix looked like it's an Omnitrix with a red color scheme.
When Albedo transforms into Ultimate Humungousaur, the spikes on the Ultimatrix symbol don't appear until after he gets fully consumed by the red light.