Mikey proves himself when he's in his own element during the Turtles' journey into Dimension X.
- 11th-Hour Ranger: It appears Leatherhead has become this for the Hamato Clan as of this episode, the last one before the season two finale.
- Asskicking Leads to Leadership: Mikey, having spent months in a dimension that accommodates his kind of madness, has become a highly trained and competent ass-kicker and usurps Leo's leadership over the group. Without Mikey's leadership, the whole plan would've failed.
- Bittersweet Ending: Leatherhead is finally saved from Dimension X and Donnie has a power source for his upcoming Turtle Mech. However, the Kraang have perfected the mutagen and their invasion has only been delayed by a day in Earth's time. Nevertheless, the Turtles - with their new addition to the clan - are ready to fight the Kraang together.
- The Bus Came Back:
- After an absence spanning a year and a half, Leatherhead makes his proper return. The length of time since his last appearance is Lampshaded, as thanks to the difference in how time passes between our dimension and Dimension X, Leatherhead is decades older.
- Traag also makes another brief appearance, with a new counterpart, who Mikey dubbed "Granitor."
- The Cuckoolander Was Right: The Turtles quickly realize something about Mikey in Dimension X: he's got this.
- Eldritch Location: Dimension X. For one thing, gravity behaves weirdly there.
- Faceless Eye: A rather HUGE one in dimension X that shoots electricity.
- Grammar Nazi: One of the Kraang corrects their own when he mispronounced sabotage.
- Impaled with Extreme Prejudice: What Leatherhead does to one of The Kraang-droids with a Dimension X Crystal Staff. We get a close up of The Kraang's terrified face before it cuts away with a Gory Discretion Shot. Afterwards, the Kraang-droid is being held up by the crystal staff, until Leatherhead removes it, and the droid falls over.
- The Juggernaut: Mikey proves to be this even moreso than Leatherhead. He never seems to be in any real trouble in Dimension X.
- Leaning on the Fourth Wall: "I wish they were real, and we were fake. ...Wait, what if we are?"
- Mythology Gag:
- The filtration units Donnie equips the Turtles with resemble those used by the Turtles in the Mirage comics and the 2003 series.
- The second rock monster that appears, who Mikey dubs "Granitor", is actually based on a one-shot character from the original cartoon, who, like General Traag, was a commander of the rock soldiers.
- No Endor Holocaust: A generous amount of the Kraang's toxic atmosphere is leaked into the lair, but the Turtles don't stop and try to give Splinter a filtration unit, or if the gas will spread into the sewers.
- The Unreveal: How exactly the Kraang perfected the mutagen is never explained.
- Shout-Out:
- Mikey giving the orders to the team as they try to stymie the invasion is reminiscent of a similar scene in The Avengers, right down to Mikey ordering Leatherhead to smash... Well, in this case, crush.
- Granitor has Godzilla's atomic breath.
- The Kraang's discussion of the pronunciation of "sabotage" is a reference to an infamous mispronunciation of the word by William Shatner on Star Trek: The Original Series.
- Year Inside, Hour Outside: Time passes much faster in Dimension X, so Leatherhead is much older and Mikey has time to get accustomed.
- You Shall Not Pass!: Leatherhead tries to pull one again to cover the Turtles' escape from Dimension X, but Mikey stops him this time and brings him home.
