* Phineas and Ferb [[spoiler: using all their previous inventions to pummel the Norm-bots into oblivion]]. What have they been battling all summer? ''[[spoiler: The norm]].'' [[spoiler: Suddenly the hateful, angry tone of "Robot Riot" makes sense. Phineas and Ferb don't really hate anything--except having to conform. To quote another movie song, "We're not content to go with the flow"]].
* In the online game, 2-D Isabella likes, not Phineas, but Ferb. This doesn't make sense until you realize that this Isabella only just met Phineas and Ferb. Our Isabella seems to have been friends with them since they were all a lot younger. A little girl would probably be interested in a friendly, creative BlitheSpirit like Phineas, but an older girl would be more likely to go for a quiet British guy. (Besides, 2-D Isabella, like 2-D Candace, has had to grow up a lot faster than her counterpart, and she acts more like a teenager whereas our Isabella acts like the young girl she still is.)
** Interestingly, in the official video game, she appears to have a crush on Phineas. Both are probably just ShipTeasing from the creators.
* (Dr.) Baljeet is the only shown member of the resistance who is still wearing his Dooferalls. As proclaimed by Baljeet himself in "The Baljeatles", he loves conformity. Of course he's still wearing his overalls!
* Why is one of the dimensions they go through a huge room with a huge person in it? Because that whole universe was expanded by Phineas and Ferb's growth elixir and never shrunk back.
** ... Didn't it [[FridgeLogic not shrink back in the growth formula episode?]]
* When Candace interrupts the movie her parents are watching, her mom says, "The girl is about to forgive the guy for the cliché misunderstanding". If you take the obviously [[RomanticComedy rom-com]]-y situation and apply it to Perry and the boys, that's pretty much what happens in the movie itself: Phineas thinks Perry was "lying" to them and using their family as a cover, and Perry has no way of explaining that he's only keeping his secret so he won't be taken away from them. Even though he doesn't talk, it's obvious that he "forgives" Phineas.
* Why are there so many gnomes in 2nd Dimension, and not in the alternative future from earlier? Because this Doof never was forced to be a garden gnome by his father and never resented them!
* Some Fridge Heartwarming has been noted on the Heartwarming page: Doofenshmirtz is unable to say what his friends nickname him. Phineas calls him "Dr. D" moments later. Taking this a step further, the song "Missing My Nemesis" in "It's About Time", sung from [[FriendlyEnemy Perry]]'s point of view, [[CallBack also]] addresses Doof as Dr. D.
* In spite of numerous references to it, Buford-2 is never shown doing much that can seriously be considered "resisting the Resistance". This appears to mirror Buford-1's status as a "bully". Both of them do/may do things occasionally that fit their reputation, but for most part it's more an InformedAttribute.
** Alternately, he's gotten so good at resisting, that he resists the resistance. So when Candace tells him to keep resisting, he resists it. So he resists resisting the resistance and is now helping the resistance as a form of resistance.
* Candace-2 states Jeremy-2 leads a three-man strike team. We never meet any of them, but in the first demension, Jeremy leads a three-man band. Could it be them?
* The train that Doof-2 loses in his comparatively mundane backstory? Look to Doof-prime's backstory about being forced to wear the girl's clothing his mother created when she thought Roger was going to be female. He starts that story off by saying that he was happy for exactly five seconds in his life--when he was pushing a toy choo-choo back and forth!
* If you take a [[AlternateCharacterInterpretation slightly different look]] at Isabella's crush on Phineas, it explains a few things, particularly her kiss at the end of the movie. She was excited to have her memory erased, even though it confirmed Phineas had feelings for her. But what if she already knows (or suspects) that Phineas loves her, and is merely upset because she's waiting for Phineas to make the first move and he's too distracted to. It matches with most of her interactions throughout the series and it makes this scene make more sense. She can have the fun of kissing Phineas without destroying her romantic plan for how things should go.
* Why is Doof-2 so much more competent than Doof-Prime? Their backstories. Doof-prime was raised by South American Wild Cats, forced to sit outside, and was the Unfavorite along with the backstory of the week. Doof-2 only lost a toy train. Doof-2 had more chances to learn and a better environment to do so.
** You could also argue that Doof-2 is more competent because he has less backstories, allowing him to focus on being truly evil, instead of getting distracted by petty grievances.
* Doof-2 sings during "Kick It Up a Notch" about "cranking up the evil" backed up by Platyborg's guitar. And this is during the credits. After the movie. Did Doof-2 and Platyborg become evil again? SequelHook?
** Probably not. The musical numbers in this show frequently defy continuity...and sense altogether. Furthermore, "Kick It Up a Notch" wasn't even made for the end credits. It's a music video that got tacked onto the movie when it was rerun.
* We never did got to see Stacy-2, which make people wonder what happened to her...
* [[spoiler:[[HereWeGoAgain Hey, anyone else remember that kid whose toy robot blew up after Doof-2 pushed the self destruct button near the end of the movie?]]]]
* When Phineas and Ferb meet their alternate selves, Phineas-2 freaks out and thinks he's being replaced for not conforming enough. How often does this happen in that dimension?
* Why no alternate Vanessa? Well, maybe alternate Doof was too much of a psycho to ever have a family. Or maybe he did have one ''and did away with them'' because that Doof would be too much of an evil bastard to take lip even from a wife or daughter.
** Wrong. She and alternate Charlene are around, as shown by a deleted scene. Their interactions with Doof-2 even seem to go just like they do with Doof-1 and his Vanessa and Charlene.
** However, they don't seem to care that Doof-2 is an evil dictator. At all.
* Speaking of Doof-2, the fact that he decided to become evil because [[DisproportionateRetribution he lost his choo-choo]] makes you wonder: [[AxCrazy what the hell kind of mindset would allow that?]] Or worse, [[EnfanteTerrible what if the train]] [[TheSociopath was just]] [[LackOfEmpathy the excuse]] [[StrawHypocrite he]] ''needed.''
** And, of course, there's the question of what he would do if he lost his new one.
** Confirmed as of ''Tales of the Resistance: Back to the Second Dimension'' where Charlene-2 throws away Choo-Choo causing Doof-2 to resume his life of evil. Not that he actually does anything particularly evil this time. Still, he and Charlene-2 did escape with some help from Vanessa-2 and her new boyfriend.
* The Platyborg doesn't seem so bad--until Doof-2 suggests that he might make ''[[BodyHorror Phineas]]'' into a robot as well...
** Speaking of the platyborg, [[spoiler:he "gets the evil shocked out of him" at the end, when he's electrocuted. And he seems pretty dang happy to be mentally his old self again]]. [[AndIMustScream You don't think...]]
*** I do think. Luckily it seems only to have been for a few months....
** For that matter, how ''did'' he turn Perry into a cyborg into the first place? Did he ''[[WeCanRebuildHim torture him to an inch of his life until his body was a twisted, bloody wreckage]]'' [[WeCanRebuildHim that could only be repaired with machinery]]? Then when you consider he almost did the same thing to ''[[WouldHurtAChild Phineas]]''...
*** And he was willing to do that to Phineas after stating earlier in the movie that ''he thought Phineas was a toddler''.
*** Actually, a comic reveals he trapped Perry in a container filled with green liquid.
* So it's the end of the movie, Doof 2 is defeated and the gang sacrifices this memory to keep Perry and we get a bundle of heartwarming moments, everything's all dandy. But then you think for a second. Our Doofenshmirtz got his memory erased just like everybody else. That means he doesn't remember giving away his train to Doof 2. If by sheer chance he wanted to find the train again, he would discover that it's lost. He would turn into Doof 2! Possibly reflecting the same actions his counterpart had did to the Second Dimension. We don't know anything about this train, but the way Doof 2 mentioned that Doof 1 could have become eviler without it, it's not going to end well.
** Nah, he didn't even remember he had it. How would he miss it if he didn't know it was there in the first place?
* This troper had recently finished watching the movie and was just watching the Christmas special, when she noticed the Doofenshmirtz family portrait. After checking on the wikia for the show, I noticed that the horns from the...freaky animal skeleton in Doof-2's lair match those on Doofinshmirtz' father's helmet. What did Doof-2 do to his father?
** It's probably just some weird Druelsteinian animal, and Doof's dad got the horn on his helmet from one of the same species.
* Previous poster again. When Phineas and Ferb run into Lawrence-2 leaving the house, he says he'll see them 'next spring'. What sort of job does Doof-2 make him and others work that requires him to leave for so long?
* And why does Linda-2 have to hide in the basement while leaving her innocent young sons exposed in the house above? Did Doof-2 also have a disastrous date with her...[[RapeIsASpecialKindOfEvil and does he come back every so often to catch up on old times?]]
* Assuming it's not a continuity error... Perry seems to have been pretty young when he was adopted by the boys. He was part of [=OWCA=] from that first day. Do...do they use ChildSoldiers?
** Well, if you remember the Museum episode, Perry only started battling Doof when he was old, so maybe the OWCA just needs families to take care of young agents while they are being trained.
* One of the scientists of the OWCA examining Doof's inventions is the woman that apparently lead the KnightTemplar parents in 'Quantum Boogaloo'. Guess about the implications of her presence in the OWCA...
** This troper doesn't get it. What are the implications?
*** I think the OP was implying that if she works there, she probably knows all about the inventions and the children who made them, and she was one of the ones who freaked out and created the BadFuture in 'Quantum Boogaloo' after finding out ''the exact same thing''.
* During the "Robot Riot" scene, the sled that Phineas and Ferb built for ''WesternAnimation/PhineasAndFerbChristmasVacation'' can be seen. However, in the chronology of the show, that Christmas hasn't happened yet.
** They could have built it the previous winter and rebuilt or uncovered it the next. There's nothing saying Phineas and Ferb didn't build any crazy projects before this summer began.
** IIRC the show takes place over multiple summers, so it could be a summer after the Christmas special.
** WordOfGod says season 3 is the next summer vacation than seasons 1 and 2, so it probably happened after.
*** But when Phineas is telling Alternate!Phineas and Ferb about the stuff they did that summer, he starts with "We built a rollercoaster, we became one-hit wonders..."
*** Candace also refers to trying to bust them all summer.
** As for the rollercoaster, they could be referring to "Rollercoaster: The Musical". I don't know about the second thing--being a one-hit wonder is inherently something you can only do once.
*** Depending of the definition of "became" used, their band in 'Ladies And Gentlemen Meet Max Modem!' qualifies as becoming an one-hit wonder.
** The Flying Car of the Future Today also appears, which would be cool as well...except that the episode it appears in is a flashback in general, so therefore, it shouldn't even be there, presuming that the boys did not invent it off-screen.
*** The Flying Car first appeared in Perry's dream, but that doesn't mean it didn't actually happen.
* During the escape from the Goozim Perry supports Phineas', Ferb's, Candace's and Doof's combine weight. If we estimate that the boys weigh about 90lbs. each and Candace (at a height of 5"6') weighs about 125 and Doof (at a height of 6" but with a beer belly) weighs about 160 AND the weight of the chain of an unknown metal so lets be nice and claim it's only 20lbs that means a ONE-AND-A-HALF-FOOT platypus is holding at least 485 POUNDS! Perry is Fricking STRONG!
** CartoonPhysics, and he's always been portrayed as a PintsizedPowerhouse. Still impressive though.