Its safe to say the premise of Jojo Rabbit is an attention grabbing one.

The sight of a comedy sidekick Hitler as the imaginary friend of a 10 year old boy is, to put it kindly, the kind of movie premise that will get people talking. That is even moreso when one considers that as the film’s director/producer/writer Taiki Waititi couldn’t get anyone to play one of history’s greatest monsters, he played the role himself.

Satire of the Nazis isn’t a strictly new phenomenon. Indeed, Hollywood produced anti-Nazi satire at the time, with Chaplin’s The Great Dictator seen as one of the favourites of that era. But it is still something of a big move now to see such heavy reference to characters in the uniforms of World War 2’s losing side playing a key role.

There are clearly audiences for the film out there. The film has 6 Oscar nominations, including a Best Picture selection, enjoys high praise on the Google fan reviews and had a broad popularity among film critics, even if that comes with some high-profile exceptions.

The film begins in the final stages of World War Two. 10 year old Jojo (Roman Griffith Davis) is a proud Nazi fanboy, replete with his Hitler imaginary friend. However, he fails to impress at a training camp, culminating in him injuring himself in a grenade-based accident and he ends up being relegated to non-combat tasks around town.

This initially means spending time with his mum Rosie (Scarlett Johansson). But when he comes one afternoon while she’s out, he hears noises upstairs that turn out to be a girl hiding in the walls in his dead sister’s bedroom. That girl is Elsa (Thomasin McKenzie), who turns out to be a Jewish girl hiding from the Gestapo, SS et all, much to Jojo’s initial disgust.

In the early stages, there is shock value in some of the gags, or indeed with a montage culled from old Nazi propaganda soundtracked by a German language Beatles song.

The early sets are also promising. Waititi owns the premise of his strange concoction, channelling Hitler into comedy while never really being too far from the strongly hateful presence of who it is. It forms a strange odd couple with Davis, who offers a fine central performance capable of tackling the emotional rollercoaster expected of him.

Davis also forms a fine odd couple with McKenzie, who has plenty of comic interludes and smirk in mucking around with the obsession of Davis’ character, while also balancing the tragedy of her role of being forced to live inside somebody else’s walls.

Johansson has received nominations for her supporting role, which has a certain degree of development that helps drives Jojo’s story. There’s also good supporting turns from Sam Rockwell and Rebel Wilson as a curious odd couple, with Rockwell’s jaded Army officer playing well against Wilson’s chirpier enforcer.

The film also looks good and has some good gags, with a mix of laughing with and at, such is the nature of a satire like this. Indeed, it is curious that after some of the Kiwi-inflected humour that helped Waititi find an audience translated to a big budget Marvel movie, its found its way to a satire of a bleak period of history, and continues even after the film finds its way down some dark paths.

The question is more as to whether the film can sustain itself when the initial surprise of the lead character’s Nazi behaviour wears off and the production settles into a more routine film. Underneath the bluster and the premise is a fairly standard coming of age narrative, where Jojo is gradually learning to question his ideals in the presence of a perceived outsider who he turns out to have more in common with.

In a strange way, the fairly ordinary ruminations of the plot make the outlandish premise seem pretty simple. It is surprising just how this gets reduced into it, but it feels like the film’s conventional style ends up diluting the shock value and the satirical potential of the movie.

Some quarters have criticised the film for being even-handed about the evilness of the leads, but its hard to truly see that when it spends a lot of time either with characters either truly against what the Nazis stood for, or who are losing faith in the self-perceived superiority, almost as a handbrake on Jojo’s enthusiasm.

Jojo Rabbit in all is an engaging anti-Nazi satire, but feels like its adherence to the conventions inherent in a coming of age story hold it back. The characters and general display is watchable and the film does answer the point of its existence without celebrating the awfulness of its characters’ beliefs. However, it feels like it misses the chance to be truly great, as it ends up feeling oddly diluted and predictable, which is not something you might necessarily expect from either premise or opening phase.