Dr. Arkeville reappears as a main character for this episode, adding a bit of needed continuity to the cartoon, as he was also a major character in the previous three episodes (previous, according to the story, not to the actual airings).
First appearance of Frenzy, though the identical-looking Rumble has already been using his actual blue-purple color-scheme since the start of the series. Frenzy, in turn received Rumble's original, red/black colors.
Since the near end of the third part trilogy story; The Ultimate Doom. Despite being blown clear of Earth's orbit. Cybertron it seems is still close enough for Starscream to manage flying all the way to it, and back to Earth. Without the need of a starship.
"Countdown to Extinction" would become the name of a 1992 studio album by Megadeth