- Mandark, as usual, has some good lines."Blast you, Dexter!! Hey, now there's an idea. Blast Dexter!" *fires at him*
- The dramatic tone of the fight between Dexter and Mandark, two kids, in the beginning, especially next to how silly they fight later on.
- Robots sent from the future arrive in Dexter's lab to presumably kill him. What does he do? Run around in a circle panicking. At least until he recomposes himself enough to fight back.
- The aftermath of Dexter winning the fight against the future robots. Dexter is excited that he is such a hero, and can't wait to see when he saves the future. Unfortunately, he hasn't considered when exactly that is.Dexter: "Dexter, the boy who saved the future! Woooo! I can't wait for the future![Beat, Dexter pouts]Dexter: "The future's taking too long."
- This whole exchange:Number 12: Oh, I've always been like this.Dexter: WROOOOONNG!
- One of the stupid villagers in the Bad Future ruled by Mandark fixes up a bed only to then go to sleep on some jagged rocks.
- During the World-Healing Wave at the end, we see several others such as one man carrying his horse on his back rather than riding it, and one man tying hammers to his feet while another is trying to hammer in a nail with a shoe. They all switch to the correct use when the wave hits them and their intelligence returns. The horse, who seemed rather content being carried, looks rather annoyed when things change.
- When the different versions of Mandark and Dexter fight, Old Dexter and Braindark just stand there and call each other names.
- The fact that only the fight between Action Dexter and Overlord Mandark looks like a typical final showdown. The regular Dexter and Mandark just engage in a nerdy slap-fight since neither of them had any training as kids, and Executive Mandark just bullies and slaps around poor 12 for most of their fight.
- Dexter realizing he started a Stable Time Loop in the ending and subsequently giving up on figuring out how everything happened while trying to make sense of it.
- While Executive Mandark is taking his Literal Ass-Kicking, streams of money shoot out of his back pockets.
- When the Mandarks realize the Dexters are running to fix the Neurotomic Protocore:Kid Mandark: No, I always wanted the core!Executive Mandark: No, I stole the core!Overlord Mandark: No, the core is mine!Brain Mandark: No, just because I'm bitter and jealous!
- The sight of all the Dexters and Mandarks locked in an eight- man chain (oldest to youngest, each Mandark holding their own Dexter back and each Dexter holding the next Mandark back) after trying to get to the core and keep the other group from reaching the core, with the three older Dexters cheering the youngest on with a chant of "Go, Dexter, go!" to press the button that will fix everything.
Dee Dee: Ooh! What Does This Button Do?
- And then, who should show up? Dee Dee! She comes out of the time machine that the Dexters welded into their nearby, now-trashed Humongous Mecha, casually strolls towards the Protocore's control panel completely ignoring the eight-man chain right next to her- then does her thing, puts her hands on her hips as if to say "Welp, my job here's done!" and heads straight back through the time machine without a second thought.
- Even better? That's her only line in the movie!
- The fact that every damn Mandark is still smitten at the sight of Dee-Dee.
- 12 is so stumped by Dee Dee's sudden arrival that he reverts back to his nerdy voice for the rest of the story.
- This hilarious exchange after the battle ends;Old Man Dexter: (Burst from the rubble) I remember! I remember! Dee Dee was the one who saved the future!
Dexter: What?! No way!
12: That didn't just happen!
Action Dexter: (In a whiny tone) I wanted to be the one who saved the future!
- Dexter and 12, in the far-future museum exhibit, walk face first into a pane of glass.12: We appear to be surrounded by a very large pane.
Dexter: I'll say.
- Dexter and 12 meeting Old Dexter in the future, asking him how he saved the future. It doesn't go very well.Dexter: We are the Dexters of the past. We have come from the past to try to reach your all-knowing presence!Old Dexter: Presents? I didn't know it was my birthday!
Dexter: You saved all of mankind!
Old Dexter: I did?!
Dexter: Yes, don't you remember?
Old Dexter: Remember what?
Dexter: How you did it!
Old Dexter: What'd I do??
Dexter: [annoyed] Saved the future!
Old Dexter: I DID?!?!
- Hearing the off-screen Old Dexter struggling just to answer his front door. "Ugh, oof... Who put these stairs here?"
- When they first meet Action Dexter, Dexter and 12 gush over his Heroic Build and Manly Facial Hair ... but are puzzled by the fact that he's become bald. Cue Old Dexter lifting his hair up and revealing he actually wears a Dodgy Toupee.
- "Goodbye, Billy!"
- When Dexter returns to his own time, he arrives there just after the robots, so his past self hasn't left for the future yet, and he watches himself fight the robots while trying to wrap his head around the Stable Time Loop he just finished. Finally, he gives up on it and goes to make a sandwich.
- In the kitchen, Dee-Dee walks up to him, only for Dexter to give her a Death Glare for what just happened and walk off with his food, leaving Dee-Dee confused over what his problem is.
Funny / Ego Trip