Alternative Character Interpretation: Soto's "I was beginning to worry about you" comment when Diego returns to the pack for the mammoth trap could be seen as Soto possibly caring for Diego as if he was his own son.
Ass Pull: Diego's survival in the first movie has NEVER been explained to any adequate degree beyond, "Well, shit, this is a kid's movie so we can't really have him die." (Although according to the creators, Diego actually did die in that scene and came back, but that just makes things even more confusing. He was originally going to die, until his voice actor suggested they have him live in the end.)
Manny in the first one. Most people liked him in the first one while some thought he was too much of a jerk. However, as he's softened, he's not exactly become a hated character, but he's been complained for being boring and being too much of an Over Protective Dad.
Crack Pairing: Many, but notable ones include Sid and Ellie/Sillie and OT3s like Manny/Ellie/Diego. Supreme crack pairings include Peaches x anyone, but these have been mainly only discussed, though Sillie has been written once.
Rudy/Buck is another example, though it also crosses over with Foe Yay. Sid/Diego probably counts as well, since there is really no viable reason to pair Diego and Sid together, let's be honest, it's Pair the Spares if anything else.
Critical Dissonance: Although the first film did get a fresh rating of 77% on Rotten Tomatoes, many critics did complain that the movie felt too similar to Monsters, Inc. and Shrek. However, the audience enjoyed it more, as it was a box office success and it's usually seen as being the best of the franchise. The second and third film also falls into this category. Despite both films receiving mixed reviews, both sequels received generally positive reviews from the general public and were massive blockbuster successes, managing to outgross the first film with the second film having the biggest opening weekend out of the entire franchise with the third film remaining as the highest-grossing film in the franchise. However, most people debate on whether which sequel is the better one. Even Continental Drift was hit with this, it received mixed reviews from critics, but earned an A- and a 62% from audiences on Rotten Tomatoes.
Critic-Proof: All 4 sequels have gotten a rotten rating on Rotten Tomatoes yet they have all done well at the box office. Even the fourth one, which was the highest grossing film of the franchise worldwide but the lowest grossing domestically, still made a profit.
Draco in Leather Pants: Some fans like to over-romanticize Soto as this. One person to such an extent that the Sub-Zero Heroes become Ron The Death Eaters, Diego especially, because of the whole "brother with Soto" fanon.
Buck is definitely this, being one of the most badass characters in a children's film ever. This might have something to do with the fact that he's a one-eyed weasel scarcely larger than Crash & Eddie, who's hunting analbino Baryonyx bigger than a Tyrannosaurus.
Also, Soto being Not Quite Dead pops up somewhat commonly in fanfiction.
One bit of fanon is that somehow, in some way, Soto and Shira are related to each other by being either father/daughter or siblings.
The implication that Runar's tribe killed Manny's family. It's never truly established as being this in the film, but fan reading of canon often goes with this conclusion.
The implication that the two rhinos at the beginning of the first film, are a gay couple. Blue Sky has given no official confirmation for this, but most fans (casual and hardcore) tend to read them as a couple, but it's still fanon. And oddly enough the world of Ice Age fanfic ignores them as well, when the fanfiction realm is well-known for its love of slash pairings. Make of that what you will.
Fanon Discontinuity: All of the sequels get this to some degree among different groups of fans, but Collision Course gets the absolute worst of it, as noted under Sequelitis. Most fans just stop at the third film, which most felt it was a sufficient conclusion to the original trilogy and didn't need any more story.
Peaches/Ethan has become this, despite Peaches seeing Ethan as shallow in the fourth film and going off with Louis at the end. Although Peaches/Louis is still pretty popular, even after Peaches married Julian in the fifth film.
Franchise Original Sin: The first film contained a decent amount of Toilet Humor (Sid stepping in the glyptodont poop), adult humor (Sid saying that a girlfriend would "go all praying mantis" on him, amongst other things), and modern references (the glacier acting like a passing bus). However, this was underplayed compared to the sequels, and the first film still had enough heart to make up for all of it.
"Funny Aneurysm" Moment: Diego's line "can't have one of your own, so you want to adopt", while only meant at the time as snark, becomes much harsher after the reveal that Manny's mate and child were killed by humans.
Germans Love David Hasselhoff: The Ice Age films have all had decent box office runs in North America, but, at least in the case of the sequels, were overshadowed by the films from Pixar and Dreamworks Animation. Overseas, the series has been very successful, withallfourfilms in the series being the highest grossing animated films worldwide in the years in which they were released.
The movies, especially the first one, gained a lot of popularity in Norway. One reason in particular being famous comedian Dagfinn Lyngbø voicing Sid with his distinct Bergen dialect, who've more than once been recognized as making Sid several times funnier than the original.
Manny's introduction. Why was he walking the opposite direction of the other animals migrating away from the freeze? It's because he felt life wasn't worth living anymore after the deaths of his original family, and was ready to commit suicide by freezing to death.
Before the heroes enter the ice cave in the first film, Sid is joking around by pretending to be impaled in the neck with an icicle. How does Soto die again?
While saying goodbye to Roshan, Manny tells him that they'll never forget him. This becomes blissfully ironic as Roshan is completely forgotten about in the sequels.
In 2002, there were no known mammals extinct or extant that closely resembled Scrat. Come late 2011, one was described and named Cronopio. (However, it was not a squirrel, but part of a now-extinct mammal group, the dryolestoids. Furthermore, it lived in the Mesozoic Era, not the Cenozoic as most of the other animals in the films are.)
The first movie had a T. rex frozen in ice as a gag. In Dawn of the Dinosaurs, the heroes find a lost world of surviving dinosaurs below ground. It led to fan speculation that the "meltdown" in the second movie actually freed the dinosaurs in the third movie.
The first movie also had a UFO frozen in ice as a random sight gag, but fast forward to the premise of the fifth movie...
Periphery Demographic: Though the films are ostensibly aimed at younger audiences, the movies — for example, the first one — have attracted a lot of teen and adult fans, who enjoy the Original for its depth, humour, dramadic elements, and tearjerking moments. The sequels have admirably brought in teen and adult fans as well, and one reason the movies have such a demographic is because young fans of the Original realised that the sequels kept up with the Original in some regards (ie emotional plots and captivating characters), since some of the teen/adult audience watch the sequels in hopes of seeing characters like Roshan again or just revisiting their old friends the herd.
The Scrappy: While Sid and Scrat have their faults, they at least contribute to the plot and give a few laughs. Crash and Eddie don't. Those Two Guys are annoying, and if you remove them from the third fourth and fifth films, the story will be completely the same. They exist only to be hilarious, only they're not, because their brand of humour - behaving like idiots - gets old after thirty seconds.
Sequelitis: The majority consensus is that the film series worsens in quality with each film. Each film has a progressively lower rating on Rotten Tomatoes, with the first film ranking at 77% and even getting nominated for the inaugural Best Animated Feature Oscar; meanwhile, the latest installment, Collision Course ranks at an abysmal 16%, and yet in spite of that, the Blu-ray cover proclaims it is "THE BEST ICE AGE MOVIE YET!".
Signature Song: The ending of "Ellie Remembers" (or in "Goodnight Sweet Possums") from The Meltdown has been adopted as the main theme of the films (it's heard in such poignant moments like the birth of Peaches, the end of Dawn of the Dinosaurs and Continental Drift. "Mammoths" has become the secondary theme of the series.
So Okay, It's Average: This is how some critics have felt about each film, even the original to a lesser extent.
Manny's relationship with Ellie, down to having a calf with her, could have been much more emotionally moving and impactful than it is, considering that he's already seen his first mate and child killed, a fact which is central to his entire character and yet has never been referenced since.
That entire herd of mammoths that appear at the end of the second movie? Never followed up on.
Tough Act to Follow: While the sequels have their fans, most will agree that neither of them hold a candle to the first movie.
Uncanny Valley: The CGI in the first film can be this for some, as it hasn't really aged very well. It should also be noted that Ice Age got an Oscar nomination for Best Animated Feature Film the year it released, thus the CGI in the first film couldn't have been that bad if the Academy approved of the work seen on the film.
What Do You Mean, It's Not Symbolic?: Manny rescuing Diego from the fiery flames of the lava. Not to mention that Roshan's role in the film is a "Peace Child" between the humans and the animals, and it's his innocence that helps redeem Diego, helps Sid find a new family, and gives Manny closure after his family's death, and reconciliation with the people who destroyed his life. It's one aspect of the Original movie - that is, Roshan's importance - that is often glossed over, but he changed all of the characters taking care of him because of his love and innocence, was central to character and plot resolutions and by the end Manny, Diego and Sid are a herd because of Roshan bringing them together as true friends.