Convicted of starting a minor border war between Norway and Finland, the symphonic post-apocalyptic reindeer-grinding Christ-abusing extreme war pagan Fennoscandian metal band Impaled Rektum serve their time in an island prison, where they are forbidden from playing anything but dance music but get to enjoy a highly regarded salmon buffet.

When bank foreclosures threaten the reindeer farm owned by lead guitarist Lotvonen’s dad, the band bust out of prison and run for Lithuania, where they have been promised a literally Faustian record deal by the impresario Fisto (Anatole Taubman). They cross the Gulf of Finland by stowing away in the tour bus of Blood Motor, a once-great band now in unstoppable decline, fronted by the doleful, leonine Rob (David Bredin).

Bass player Xytrax (Max Ovaska) sees Fisto for what he really is, and refuses to have any truck with his desire to dumb down Impaled Rektum’s sound by adding… urgh… synthesisers and friendlier fonts. He even wants to put drummer Oula (Chike Ohanwe) in lederhosen, which only a psychopath would ever do. But lead singer Turo (Johannes Holopainen) is eager to please and tempted by the allure of fame, prepared to repeatedly compromise and even forgetting that the band are supposed to be in this for the money to save Lotvonen’s farm.

Partway through Juuso Laatio and Jukka Vidgren’s joyous Heavier Trip (a sequel to 2018’s Heavy Trip), German news reporters descend on a crime scene in Rostock, where a museum of priceless rock memorabilia has burned to the ground during a fight started by a Finnish death metal band. They push a microphone into the face of a dazed Norwegian witness, who mumbles: “Monarch to the kingdom of the dead, infamous butcher, angel of death.” All the Slayer fans in the cinema cheered.

So… just me, then. Not for the first time at a Finnish comedy film, I was the lone laugher at many of the jokes: the eternally flaming guitar of Jimi Hendrix; Lou Reed’s old liver, preserved in a jar; Dave Mustaine’s six-fingered hand; Lemmy from Motorhead’s hat (“If hats could talk, this would be a very traumatised hat”), and the sight of a very small Stonehenge.

But it’s the music that is the real star of Heavier Trip, with composer Mika Lammassaari presiding once more over truly loving, thumping recreations of rock classics, from the “found” sounds of a malfunctioning washing machine, to full-blown death-metal epics. I was left alone in the cinema as the credits rolled, waiting for the closing list of song titles and arrangements, sure that somewhere in there was a thrash metal cover of Barry Manilow or something equally crazy (sadly, no), as well as a bunch of bands that I thought were throwaway joke names, but turned out to be real. The (fictional) Blood Motor’s performance is fantastic, until the ailing Rob is dragged into the crowd by shrieking groupies, and Turo has to step up to the microphone to finish his song for him.

Heavier Trip is unapologetic in its celebration of heavy metal, both the bombastic, pompous form of, say, Celtic Frost’s Into the Pandemonium, and the sell-out, commercial folly of…. well, Celtic Frost’s Cold Lake. Xytrax struggles with his disdain for the perky Japanese rockers Babymetal, despite overwhelming evidence that they are just as hardcore as he is, just in a different way. As he sits, dejected at a bus stop, mirroring the set-up for a famous scene from My Neighbour Totoro, he encounters not a Catbus, but Babymetal’s tour van – the real life Babymetal play a pivotal role in the film, but seem to leave it a scene too early, as if they were afraid of turning into pumpkins.

Many of the gags will fly over non-metal heads. Fisto takes separate phone calls from someone called James and someone called Lars, which only Metallica fans will understand. Turo gains a pair of bat wings modelled on those of the Eurovision game-changer Lordi, and nobody asks why Norwegian rockers Abbath seem to require a fresh corpse backstage as part of their performance conditions. But there are also some lovely little gags that will only hit home with Finns, such as the moment that Mrs Lotvonen (Sinikka Mokkila) respectfully tries to address Xytrax by his preferred band name, but instead calls him Zyrtec, the name of an over-the-counter anti-histamine.

Few of the small-town supporting cast from the first film are to be seen here – there is no sign of Turo’s lounge-singer nemesis, or florist would-be girlfriend. Apart from the reindeer-farming Lotvonens, who provide the McGuffin that gets the band out of jail, the only other holdover from Heavy Trip is Ms Dokken (Helén Viksvedt), unconvincingly demoted from border guard to prison guard in order to give the film someone to chase the band across Europe.

Sometimes, it does seem that there’s rather a lot going on – including the chase plot as Dokken pursues her escaped prisoners and the gotta-save-the-farm plot that is largely forgotten and resolved in a hurry over the credits. But the real heart of Heavier Trip is the band’s clash with the world beyond the small-town fame of the original film, in the dog-eat-dog struggle of bands that have found success, but don’t know what to do with it. It is quite literally the “difficult second album” of the saga of Impaled Rektum. Surely a Heaviest Trip awaits in the future…?

Jonathan Clements is the author of A Short History of Finland, the country with the largest number of metal bands per capita in the world.