It feels like a momentous occasion to watch a new Hayao Miyazaki film. The Boy and the Heron marks his first feature-length work since The Wind Rises a decade ago, and sees the acclaimed director return from a self-imposed retirement. It is a difficult film to sum up and assess in a few hundred words, because really it is going to be judged on two levels: not simply whether or not the film is good, but whether or not it is so exceptional that it ranks alongside Miyazaki’s other work. He is to my mind the single-greatest animated filmmaker of all time, and several of his works – chiefly My Neighbor Totoro and Spirited Away – rank among the greatest films ever made in any country, decade, or medium.

The answer to these two questions are, respectively, yes and no. There is no questioning that The Boy and the Heron is beautifully animated and handsomely designed, and boasts strong voice acting (I watched the English language version). Regular collaborator Joe Hisaishi provides another wonderful musical score. All of the visual motifs of Miyazaki’s films are evident: food, flight, and the rural Japanese landscape all figure prominently. At the same time there is something lacking in the screenplay. There is a sense that far too much story is left undefined or unclear. I actually suspect it will prove a more watchable film the second or third time around. On the first viewing the pace drags badly, and the innate charm that energised the likes of Kiki’s Delivery Service or Ponyo feels missing. On first reflection, more comparable films would include the likes of Princess Mononoke and Howl’s Moving Castle: very good, but we have been trained to expect brilliant.

The film opens on war-time Tokyo, where young Mahito Maki (Luco Padovan) loses his mother Hisako in a fire. Three years later, Mahito moves out to the countryside with his father (Christian Bale) – a munitions manufacturer – has married Mahito’s aunt Natsuko. Almost as soon as he arrives at the family estate, he is trailed by a mysterious grey heron (Robert Pattinson) and intrigued by an ominous ruined tower on the edge of the estate.

The contents of the tower leads Mahito on an Alice in Wonderland-like journey through a strange fantasy world, which in many ways brings to mind Chihiro’s similar journey in Spirited Away. While that film presented a rich environment heavily indebted to Japanese folklore and culture, the world of The Boy and the Heron feels much less detailed and more abstractly realised. It all feels less than the sum of its parts: there are many scenes and moments of humour, lightness, and whimsy, but it simply never feels like there is quite enough. An oddly sullen tone hangs over much of the film. More than once I was reminded of fellow anime director Katsuhiro Otomo. Heron resembles his films, including Akira and Steamboy, in terms of pace and tone – and the odd rolling cataclysmic explosion.

There is a good chance that my disappointment is unfair on Heron. It is certainly a film that I would like to revisit in a year or so to give it a second chance. If this is the case, however, it is a prejudice of Miyazaki’s own making. Nausicaa of the Valley of the Wind, Castle in the Sky, Porco Rosso, and all his other aforementioned films have simply raised the bar so high.