The Lego Ninjago Movie is the third Lego-based feature in a franchise that shows no signs of slowing down. It's also the first to take place entirely within an original Lego trademarked setting – the city of 'Ninjago' – and for its first half-hour feels like little more than an extended, big-budgeted commercial. Indeed, with the appearance of each new character, don't be surprised to see kids jumping out of their seats and pointing at the screen with gleeful recognition

Still, while the film does its job as a marketing exercise from the get go, in terms of plot it takes a while longer to find its feet. Every day the evil Lord Garmadon (Justin Theroux) launches attacks upon the city from his evil villain volcano, and every day he's repelled by the colourful school-kids-cum-ninjas, the leader of whom is secretly Garmadon's own son Lloyd (Dave Franco). It's only once the lad's secret identity is revealed that the story shifts gears into something of a father/son reconciliation story – and while that's pretty familiar territory for the Lego franchise, it also provides the best material for the remainder of Ninjago.

As with The Lego Movie and Lego Batman, this third movie utilises remarkable technology wherein almost everything on screen is assembled from computer-generated Lego pieces. Like the previous films, too, Ninjago is very self-aware, particularly regarding the Lego-ness of things like the absence of fingers and the way a Lego head can become stuck in the base of a Lego foot. It's these little flourishes that immediately feel familiar to anyone who's played with the toys before and, especially for adults, spark a pleasing nostalgia-based smile whenever they arise.

The characters themselves, however, are noticeably less nuanced this time around, with only Lord Garmadon (played as a none-too-subtle parody of Donald Trump), Lloyd and Master Wu (Jackie Chan) offering any semblance of depth. The other five ninjas do provoke the occasional laugh but seem well below the calibre of the actors voicing them (Kumail Nanjiani, Zach Woods, Michael Peña, Abbi Jacobson and Fred Armisen). And yes, for those playing at home, you did count that correctly: six heroic ninjas, five of them male, which raises the age-old LEGO question: "uh...where are all the girls at?"

It's a problem with which Lego is all too familiar. An internal review conducted by the company in 2008 revealed the damning statistic that 90% of its sales were directed towards boys rather than girls. Lego's response was to launch Lego Friends in 2012 – a toy line specifically intended for girls. Pretty smart move as it happens, with the company's annual profits shooting up by around 15 percent ever since.

It's therefore both surprising and extremely disappointing that that same approach isn't being seen in the films. The Lego Movie's most kick-arse character was Elizabeth Banks' Wyldstyle, yet she was the only notable female in an otherwise male-driven story whose live action component centred upon a father/son bonding experience. Lego Batman, too, included only one notable female character in Rosario Dawson's Batgirl, and focused on the relationship between Bruce Wayne and the orphan boy Dick Grayson. Now we have Lego Ninjago, which not only suffers from a dearth of female characters but again deals largely with the father/son relationship between Garmadon and his estranged kid Lloyd. The only bright light in this situation is the announcement that The Lego Movie sequel will focus specifically on gender issues and the way boys and girls play with the toys in different ways.

Solid fun for the kids and amusing enough to keep adults interested, whilst The Lego Ninjago Movie is the weakest entry in the franchise, it's still entertaining enough to satisfy.