From the prominence of Star-Lord’s 1970s Sony Walkman (the devices now fashionably ‘retro’ are being dusted off and sold for hundreds on eBay) to the joyous and irreverently incongruous pop-rock soundtrack, music is as integral to Guardians of the Galaxy’s appeal as the comic-book mythology that it adapts. Writer-director James Gunn’s follow-up is very much the ‘second album’ to his 2014 surprisingly successful first instalment. Fortunately, Vol. 2 recaptures the same satirical, silly fun with characters and a plot as equally bombastic and sentimental as the first hit. Its fantastic cast return with reliable wit and warmth as they embark on another galaxy-wide romp through the wider Marvel universe. However, Vol. 2 also suffers from that deflating music phenomena- ‘second album syndrome’. For all its frenetic energy and its banter, Vol. 2 feels distinctively less fresh than the first go-around and, at times, is just going through the motions.

Each of the Guardians, Gamorra, Star-Lord, Drax, Groot and Rocket, are far more charismatic and likeable than their smug, self-absorbed counterparts in The AvengersIron Man and Captain America franchises.

It’s a day in the life of our ‘Guardians’ when the film opens- fighting tentacled, teeth-lined blobs with gusto, laser-beams and a lot of sniping and bickering with each other. However, Rocket (voiced by Bradley Cooper) decides to deceive their benefactors, a golden-skinned, narcissistic race called the Sovereign, his selfish prank forces the group to go on the run from foes old and new. It starts to widen a gulf between them that exists just beneath the sarcasm. Complicating matters is the appearance of Peter Quill’s (Chris Pratt) absent father, a celestial being aptly named Ego (Kurt Russell). Meanwhile, Gamorra (Zoe Saldana) takes charge of her vengeful, psychopathic sister Nebula (Karen Gillen) to resolve some deep-rooted issues in their sibling rivalry. Will the Guardians survive the challenges that not only threaten to destroy the cosmos but their surrogate family ties which hold them together?

As with Guardians of the Galaxy, the real joy of the franchise lies in the cast’s repartee, clashing character personalities and genuine affection for each other. There are superb one-liners in this; brimming with black, snappy humour or just pure silliness. Drax (Dave Bautista), who I recall was quite laconic and gruff in the first film, really shines in this regard. All blunt, socially awkward pronouncements and belly-aching laughter, he gets some of most hilarious remarks here: ‘You need a woman who’s pathetic- like you’ or ‘You are beautiful- on the inside’. However, all rise to the occasion, even if the ‘Baby Groot’ (voiced by Vin Diesel) gimmick did threaten to become irksome not even five minutes into Vol. 2. Each of the Guardians is far more charismatic and likeable than their smug, self-absorbed counterparts in The Avengers, Iron Man and Captain America franchises. There were only few instances when I wasn’t laughing, even in spite of the more corny jokes, or smiling at the banter between them. In many ways, Guardians seems to bridge the gap between the relatively humourless Marvel Hero outings and Fox Studio’s Deadpool. Where that film’s satire is caustic and often violent, Guardians is a light-hearted send-up of superhero and space operas alike- which means fortunately it rarely takes itself that seriously. Even the sentimentality, the heartstring pulling as Quill finds himself caught between real dad Ego and ‘foster father’ Yondu (Michael Rooker), isn’t without some upending humour. A scene where Ego shows Quill their god-like abilities, very much Zeus and Hercules, is played for laughs as they toss a cosmic-energy ball like it was father-son baseball bonding time in the back yard. However, Russell turns in a typically uninteresting, almost nonchalant, performance that makes you wonder whether his inclusion, like David Hasselhoff and Sylvester Stallone, is more of a self-aware joke than a character.

The trope of a newly formed surrogate family threatened by its biological equivalent is serviceable here, but lacklustre. There’s nothing new here, almost a pastiche of Dreamwork Animations’ Kung Fu Panda 3.

The humour is the foreground to a vivid and arresting production design, exploding with digitally-generated lurid backdrops and psychedelic effects. Often these seem to be a mix of Douglas Adams’ strange worlds in Hitchhiker’s Guide to the Galaxy and Electric Light Orchestra’s album artwork by Kosh and Shusei Nagaoka (Out of the Blue inspiring the design of the Sovereign). It grows increasingly bold, frenetic and often hilarious. However here is where the film begins to sag, for the many explosion-filled, nauseating action sequences are so saturated in nebula-bursting sprays and epileptic inducing flashes that I often switched off. The eclectic mix of pop and rock soundtrack, from E.L.O’s Mr. Blue to Cat Stevens’ Father and Son, infuse each sequence with an often ironic upbeat-ness though often playing disturbingly against the actions depicted, such as Yondu and Rocket’s unmerciful massacre of space-pirates carried out to Jay and the Americans’ Come A Little Bit Closer. Pop culture references are abound, from within Marvel lore to 80’s computer fads, but it all threatens to become a bit predictable. When 90s celebrity cameos, such as Ving Rhames (Mission: Impossible) and Michelle Yeoh (Crouching Tiger, Hidden Dragon) are as thrown in as Glenn Close and John C. Reilly from the first film, when we await the next inevitable sequence of pop music attached to violent action, there’s an undeniable feeling its getting repetitive. It’s as if Gunn knows what makes the formula work from a cinematic and even writing perspective and just plays to these continually, often without innovation. These ingredients often do work, but when you know what’s coming, it somehow makes the experience a little staler.

This continues into the advancement of the Guardians’ story. Moving on from a plot involving a disparate group of warriors and an origin story similar to Kurosawa’s Seven Samurai and Abrams’ Star Trek in Vol. 1, Vol. 2 goes for a near pastiche of Dreamwork’s Animation Kung Fu Panda 3. The trope of a newly formed surrogate family threatened by its biological equivalent is serviceable, though also feels somehow lacklustre. While this particular trope allows Rooker’s Yondu some needed character development beyond the hostile, sneering pirate in the first Guardians, it also felt a little contrived. This doesn’t mean that Gunn doesn’t take risks with the continuity or the conventions, especially considering the film’s sombre finale. However other characters, like Pom Klementieff’s empathic Mantis, while are amusing, often feel superfluous. With its core team pretty tight already and becoming as beloved as any 80s family-adventure film characters (think The GooniesStar WarsBack to the Future) these supporting players often become little more than necessary cogs of the plot.

Like the first film, Gunn’s Vol. 2 concludes with a James Bond-esque ‘The Guardians Will Return’ and my reaction to a third adventure is only tentative enthusiasm. This outing has all the wonderful, familiar humour, hijinks and warmth of the first Guardians and for that Gunn’s follow-up can’t be faulted. Yet its reliance on the kind of nostalgia for bygone 80s/90s family adventure films (the nostalgia that made Netflix’s Stranger Things and every recent ‘soft reboot’ a critical and commercial success) and on its own formula, can only play for so long.