After 93 episodes, the second sewer lair (it was once established by the Entity) has finally been trashed. Since the first ep. "Things Change", their first home destroyed the robot mousers.
Back in the episode, "Meet Casey Jones" Raphael was going to injured Michelangelo because of Raphael's anger until Leonardo stops Raphael and asked him 'Have you lost your mind?!'. Now in this episode, it is Leonardo's anger that injured Splinter that Raphael asked Leonardo 'What the shell is your problem?!'.
Episode centers around Leo.
The "flashback" scenes of the other 3 turtles and Splinter never actually occurred.
This marks Usagi's first appreance in Season 4.
Closed Captioning Error:
When Don fires a missile at the Purple Dragons tailgating the Battle Shell, Leo compliments him by saying, "Way to go, Donny!" However, the closed captioning shows Mikey saying the line.
Besides the fourth season theme song, this is the first time Stockman's new exo-suit is seen. Bishop also is sporting new armor in this episode.
In the opening scene before the theme song, you can see Donnie sitting in the front seat next to April, but in the episode, Leo's the one sitting in the front seat.
WE learn that Splinter used to take the Turtles trick or treating when they were little since they couldn't go out any other time.
In the prologue, one of the kids is dressed as a Teenage Mutant Ninja Turtle with a red mask (Raphael).
Adapted from Mirage's TALES OF THE TMNT #3, with some small alterations (e.g. the King of Thieves picks a man's pocket on the street rather than while disembarking from a plane, and the scene with the man's accomplices being fatally poisoned is totally cut).
According to Splinter, Mikey actually has the most natural talent for ninjitsu, and could be as good as, if not better, than Leo... that is, if he trained as hard as Leo and didn't goof off so much.
When Leo saves the Ultimate Ninja, Kluh's father said that no one could defeat 3 Levrom Warriors but Leo was fighting 4 of those guys.
How come that judge for the Battle Nexus Tournament is still alive? He was the first person to get sucked into the rift.
The Turtles are rowing past the power plant, and the cooling towers are still shown on top of the plant. However, the plant had exploded, so they shouldn't be there. In the next scene, though, the cooling towers aren't there.
If you look at Leo's shell, a piece of it is missing. This is noticeable throughout the fourth season but the shell is healed/complete by the next season.
Sid was mentioned back in the "Tales of Leo" episode.
If Leonardo was stabbed, then why didn't we ever see his wound or any blood? Logically he would bleed wouldn't he?
Splinter: Wakarimasu. I understand.
Wakarimsu means "I understand" in Japanese. Splinter uses the Japanese word, and follows it with its direct translation. This is common for uses of foreign words when subtitles aren't used.
This is the only time the Turtles fight the Shredder while he's not in his armor.