The first How to Train Your Dragon was a special kind of miracle. A simple tale of a father and his son, of a boy and his dragon, it soared beyond its modest ambitions. HTTYD succeeded thanks to gorgeously composed and edited animation and a spectacular Oscar-nominated score, yes, but mostly because of the simplicity at its heart. The scenes where Hiccup (Jay Baruchel) and Toothless took to the sky were thrillingly constructed formally, but they flew because of the bond that resonated between boy and dragon.

Arriving four years later, sequel How to Train Your Dragon 2 promises to reach the same lofty heights in its opening minutes. We swoop joyously through a Quidditch-esque game above the skies of Viking village Berk, as Astrid (America Ferrara), Snoulout (Jonah Hill), Fishlegs (Christopher Mintz-Plasse) and twins Ruffnut (Kristen Wiig) and Tuffnut (T.J.Miller) jostle for the most points (sheep), before joining Hiccup and Toothless on a flying sequence every bit as exciting as the scenes from the first film. This celebration is punctured, as of course it must be, by the introduction of conflict in the form of dragon trappers working for the mysterious Drago (Djimon Hounsou), and we shift into the necessary narrative, some of the joy bleeds out of the film.

Not that HTTYD 2 is a joyless experience, by any means. It’s as colourfully animated as its predecessor, with puppyish designs for the dragons ensuring that otherwise wearisome exposition is enriched by zippy humour. But the density of the storyline – built around Hiccup encountering his long-lost mother (Cate Blanchett), a dragon rider herself, and defending Berk from Drago and his formidable dragon army – distracts from the wonderful character development that made the first film so special. Hiccup’s burgeoning bond with his mother, for instance, had the potential to reach the same highs as his bond with Toothless from HTTYD, but it’s granted too little screentime.

Screenwriter and director Dean DeBlois, who also helmed the first film, is limited somewhat by the choices made in that film. HTTYD had a powerful message: with faith in your own unorthodox abilities, conflict can be resolved through understanding and tolerance. With the exception of the “final boss” dragon, there were no bad guys or good guys – simply two societies caught up in seemingly inextricable warfare due to the weight of history. The story was built on internal, not external conflict, and concluded with a brilliant happy ending – one that presents few opportunities to power the sequel with internal conflict, thanks to the utopian symbiosis forged between humans and dragons.

HTTYD 2 takes a less optimistic approach. Drago is a conqueror, a warlord, a man without pity or empathy. He’s a Bad Guy. Hiccup’s strident belief that he can reason with Drago proves groundless; where the first film viewed conflict with optimism, here it’s seen with overriding pessimism. This is a darker movie. Battles and lives are lost. That darkness extends to the palette, which is grey and grim as often as it is kaleidoscopically colourful. It remains beautifully animated, thankfully (there’s one gorgeous scene in particular, a cave lit only by dragonfire, that made me unsurprised to see Roger Deakins listed as “visual consultant” in the credits).

I’m certainly being too picky here. How to Train Your Dragon 2 is consistently entertaining, with an engaging plot, effective humour and gorgeous animation. It’s just that it feels crippled in comparison to the first film; trapped on the ground when it had once exuberantly ascended to the heavens.