How To Train Your Dragon: The Hidden World and Dragonheart. If you squint a bit (or a bit harder), the movies seem to sport some similarities in terms of the plot. Both movies feature protagonist who befriended a dragon. They end in very roughly similar way, too — with a sacrifice and the protagonist and his dragons separated forever(-ish — Hiccup gets to see Toothless once more, but the separation is a bit more permanent in the case of Dragonheart).
Despite both movies share some mild similarities and end in a bitter-sweet way, one of the movies is among my favourites — and the other is … well, on the other side of the spectrum.

Of Meaningful Endings and Satisfaction
Some people will tell you that bittersweet endings are often more meaningful than happy ones. They’re certainly a bit rarer than happy ones, for sure — but more meaningful? Well, it’s only meaningful if it’s justified. If the ending is arbitrary or feels arbitrary, that undermines any meaningfulness of the movie.
In order for the ending of that movie to be justified, one needs to start with one simple question: what reason does the movie give for it’s ending? In case of Dragonheart, the question is what reason does the movie give for Draco’s death; with The Hidden World, it’s what reason does the movie give for departure of dragons.
If the movie was any good, you could point at some scenes and say that they have to leave because in this scene, that happens. Once the proverbial bucket is full of answers, it’s time to ask some follow-up questions: could a movie support a different ending without any changes? Does anything (be it actions of the protagonist, an event, or general worldbuilding of the movie) contradict the reason the movie gives? Protagonist could, in theory, always take make a different decision in the end — but if the movie is good, it will not only justify the decision the protagonist took, but it also needs to show that decision the protagonist made is absolutely the best possible one. It needs to show that other options are either bad of non-existent.
This is what makes endings feel fulfilling and satisfying and deserved.
Quick side note: exceptions exist. There’s entire movies, books, and games that intend to show that at the end of the day, your decisions don’t matter. Dragonheart and How To Train Your Dragon largely don’t fit this bill.
Meaningful endings are similar, but they often contain something extra. In case of Dragonheart and The Hidden World, this something is protagonist making a sacrifice for the good of others. However, in order for the sacrifice to have any meaning, the movie has to — as I’ve said before — show that “good of others” absolutely and undoubtedly cannot be achieved without said sacrifice.
Consider, for a moment, Dragonheart

Dragonheart has its flaws — especially in the dialogue department. But despite its less than inspiring score on IMDB (probably stemming from the fact that before the success of Lord of the Rings, fantasy movies were often seen as inferior just because they were fantasy), the plot of the movie is rock solid and the writing is sharp.
Most importantly: Dragonheart justifies its ending very well.
The movie starts by future king Einon training with Bowen, a knight who highly values honor and other knightly virtues. The movie establishes very early on that Bowen hopes to teach Einon the virtues, but is as quick to suggest that Einon isn’t very receptive to his teachings. After training is over, Einon ends up rushing straight into the middle of a peasant revolt and gets himself impaled on a sharp stick. He’s rushed to a dragon — proper dragon, not a wyvern, voiced by none other than Sean ‘this is how dragons would sound if they could speak’ Connery. The dragon takes some pity on the boy and donates him half his heart, saving his life.

Bowen — thankful that Einon’s life is saved — wows to do whatever the dragon asks of him, whenever there’s a need.
As the — now current — king Einon gets better, he starts treating the workers in his quarry (prisoners from the peasant revolt at the beginning) in ways cruel enough to make working in an Amazon fulfillment center feel like a holiday in a five star hotel. Furthermore, Einon takes plenty of joy in being cruel and seeing peasants suffer.
Bowen doesn’t. Furthermore, he even blames the dragon for Einon’s behaviour, thinking the lizard bewitched the king. After all, how could a boy with a teacher like him grow up to be this devoid of all virtues? He returns to the dragon’s lair and gives a new wow: to hunt him down, no matter what it takes.

In the next dozen or so years, Bowen is in full Grimmel mode, killing dragons left and right. Eventually, he founds a dragon who offers him an alternative, to which Bowen eventually agrees. By day, the movie shows the duo conning Einon’s lords out of money with a pretend-dragonslaying scam; by night, the movie keeps reminding us that the heart bounds the dragon with the king: every time Einon gets hurt, it’s the dragon who feels the pain.
Eventually though, their con runs to an end. Along the way, the duo picks up a woman by the name of Kara, who — to keep a long story short — convinces Draco (and later also Bowen) to help her start a rebellion against king Einon. Rebels march at king’s castle. King notices the marching peasants, gets angry and rides out of the castle to attack them.

During the attack, the king gets shot through the heart. King survives, taking no damage from the attack; while the dragon is seen falling into the castle courtyard, where he is bound by king’s men. Bowen — who now considers Draco his friend — and Kara make a rescue plan. In the evening, they break into the castle, but are quickly discovered by king Einon.
Fight happens and eventually ends with Einon falling from the castle roof into the cellar. With Einon out of the picture, Bowen gets to Draco and discovers that he’s got roughly two options:

Kill the dragon or kill the dragon.
By this point, the movie has made it pretty clear that Einon cannot be killed. Draco even tells us that only his half of the heart holds the life force, that he must be killed in order to get rid of Einon, which disqualifies that option.
Keeping Einon alive and rotting in the dungeon seems inviting idea at first — until you remember that Draco feels Einon’s pain (the movie shows this at various points). In addition to that, the movie shows us that the fall broke Draco’s wing:

Which suggests that even if Einon’s suffering wouldn’t cause pain to the dragon, it’s very likely that Draco would never been able to fly again. Remember Gobber’s mantra?
This only really leaves Draco’s death the only possible ending for that movie. It also fulfills both oaths Bowen made to Draco: his oath to kill him for corrupting Einon, as well as his oath to serve him for saving Einon.
For everything that happens in the end, there exists a trail of earlier movie scenes that justify the events that happened. It makes up rules of the game and then never ever breaks or contradict them. This is what makes for a good plot. This is what makes for good writing.

The Hidden World: (Not) Discovering Something That Doesn’t Exist
If you paid attention during the previous section, you might have noticed that Dragonheart keeps doing things that keep justifying everything that happens later down the line. If you ask yourself: “why does this happen in the end of the movie,” you can point at multiple scenes justifying that and none that dispute it. Meanwhile, The Hidden World might just as well be giving a monkey a shower.

You know what? You’re probably here from reddit, so you probably know my opinion on The Hidden World. You’ve probably seen it over half a dozen times by now. I probably don’t need to include the rest of this post, but just for the sake of completeness — here’s how The Hidden World compares against that. TL;DR: it disintegrates faster than Challenger on its last ride up.
Earlier, we established that in order to justify the ending, we have to do two things. We need to ask ourselves: what reason does the movie give for departure of dragons? Finding a few things that could sorta work as an answer is reasonably easy. Unfortunately — unlike with Dragonheart — the answer to the follow-up questions (could a movie support a different ending with no changes? and does anything contradict the reason the movie gives for departure of dragons?) is most certainly not a resounding ‘no.’
- Dragons have to leave because one day, trappers might become a real threat
That’s a very hypothetical answer that’s not very satisfying. Worse yet, the movie disagrees big time. In battles with Hiccup, dragon trappers are shown to be incompetent beyond help and seem to pose no real danger. Their defeat comes easy.
- Berk is not safe from trappers

Let’s just say that the worldbuilding somewhat disagrees with that one.
- The Hidden World is safer from trappers
If you take what movies tell you at face value, yes. It doesn’t check with the worldbuilding that the movie does, though. If you consider that trappers know of New Berk, can whip up infinite number of ships, are adept at their job when Hiccup is not around and that we know that lifts exist, the answer changes a bit.
The answer changes completely once you consider that the waterfalls are shallow water and would thus allow you to land there (by running ship aground) — and let’s not forget about all the rocks sticking above the water.
- Toothless is now king of all dragons in The Hidden World, he has to be there
Why does he have to be? Neither this nor the previous movies give a compelling reason. The “chief protects his own” theme works well enough even if it’s only limited to dragons and wyverns of Berk. Furthermore, what did he do to earn his place as the leader of The Hidden World?
- Thotfury fears men (or some other thotfury bullshit)
Let’s forget that light fury grows less and less hostile towards Hiccup and Berkians throughout the movie. That alone would be enough to negate the separation, but as I said, let’s forget about it. Let’s pretend this is a good enough reason for Toothless to leave (which it isn’t). Why do all the other draconids have to leave with him?
- Dragons do what alpha tells them to do
So why doesn’t Berk move with dragons and wyverns to The Hidden World?
- Dragons attacked Hiccup and Astrid when they found them in the hidden world
So, in other words, dragons don’t do what alpha tells them to do. Why does every dragon follow Toothless and thotfury?
- Dragons do what alpha tells them to do
The search is a mystery, ain’t it? Deja vu is hitting so hard you can basically hear the song now. But we won’t be doing infinite loops.
- Humans physically can’t live in The Hidden World
There’s not a single scene or anything in the movie that would serve as evidence of that.

Another question that pops up regarding the separation — why can’t dragons visit?
- Dragon trappers could follow dragons to The Hidden World
Wonderful how the “but it’s impossible to find and raid the hidden world” excuse goes out of the window the moment you ask that question. Besides — what is night?
Discrepancies like this make for a bad writing
The truckload of contradictions and no solid justifications we see in The Hidden World makes the ending feel arbitrary — and that makes it not very satisfying and even less meaningful.
I am sorry, but this is not good writing. How To Train Your Dragon franchise was built on something much better than that.