Goof: Keith is supposed to be going to blue lion, but they show him going to black lion.
There is, apparently, an edit for violence in this episode's finale battle. Just before Voltron forms the Blazing Sword, Yurak got hit by some Proton Missiles and then fires lasers from his finger tips at Voltron. After the sword is formed, in the next sequence, there's a gaping hole in Yurak's stomach. This wound is not where the Proton Missiles struck him.
The episode of King of Beasts GoLion used to create this episode of Voltron is titled "The Crown Prince of Hell". In that episode, when Prince Imperial Sincline (Prince Lotor in Voltron.) makes his entrance into his father Emperor Diabazaal's (King Zarkon in Voltron.) castle, he has his servants carry in a large tray. On that tray are the severed heads of the leaders whose worlds Sincline conquered in the name of the Galra Empire.
Prince Lotor makes his first appearance in this episode.