If Gwen were to remain in her Anodite form, she wouldn't be able to recognize Ben or Kevin. It would also take her 75 years to master the Anodite skills.
We see a glimpse of a new Alien Profile on the Omnitrix at the end of the episode before Ben hits the watch. Known later as Lodestar.
Ben: Grandpa Max!
Manny: And Max Force!
Grandpa Max: I told you before about calling us that.
Manny: But I think it sounds cool.
Azmuth: Are you inferring that you're smarter than me because your head is bigger?
Brainstorm: No. I'm implying that I'm smarter than you because my brain is bigger.
Swampfire demonstrates two new abilities:
1) The ability to regenerate his head, as seen when the HighBreed Captain punches it off.
2) The ability to produce seeds which quickly sprout into vines and entangle his opponents.
Swampfire gains a new transformation sequence in this episode.
The Omnitrix mentions 'recombinant DNA' when repairing the DNA of the Highbreeds. Recombinant DNA is formed by taking a chunk of genes out of a DNA strand and putting new genes in its place, forming new characteristics, like the Highbreeds' new looks.
This is the first time Gwen actually releases her Anodite inner self.
Although the grey HighBreed Captain said that Max failed to defeat him, he is not the same HighBreed from Max Out who was thought to be either killed or sent to the Null Void as revealed and confirmed by the show's story editor, Dwayne McDuffie which would explain the different voice actors. He was the head guy on Earth, which means he was talking about Max failing to defeat the HighBreed in general.
Kevin's car is completely destroyed during the invasion. At the end of the episode he leaves to get a new one at te Auto Show.
Rynie has become the new leader of the Highbreed race, after his wisdom inspired the former leader.
At the end of the episode, Ben gets all new aliens, instead of his previous ones.
Alien Form(s) Used:
In addition to Pierce, Manny, and Helen, Cooper and Alan become pupils of Grandpa Max.
Grandpa Max, Manny, Helen, Pierce, and Reinrassig III return in this episode. However, Helen and Pierce have no dialogue.