You'll see reviewers calling this a Hong Kong version of The Mod Squad, by which they mean the 1999 film rather than the original 1968-1973 TV show. This is silly. The Mod Squad flopped at the box office and the critics hated it, while Gen-X Cops was a huge hit that launched a career or two and got a sequel the following year.

That said, Gen-X Cops didn't get a free ride from the critics either. There was ambivalence. Some called it slick, well-made and Hong Kong's best action movie of the past few years, while others wrote it off as a cut-and-paste of Hollywood output. Personally I liked it. It's big, it's entertaining, the action's great and the story more or less makes sense, which is a bit of a surprise in a Hong Kong action film.

We begin with a bullying tattooed gangster who makes his girlfriend cry and greets his brother by kicking him in the stomach. The girlfriend likes this. Our hero is an arms dealer who's had a business hiccup, which involves the yakuza, some bikers, some spectacular car-trashing and some killings so gratuitous and evil that they become funny.

This starts the movie with a bang. You can't trust anyone in the underworld. We now turn to the police and it becomes clear immediately that they're no better. This film is blurring the lines between law-breaker and law-enforcer, with the Gen-X Cops veering from one side to the other and making allies and enemies on both sides. They're treated as scum by other cops who actually are scum, such Superintendent To (Moses Chan) who'll sneeringly shoot down the ideas of someone short and fat before he's even listened to them, or Inspector Tang (Wayne Lai), their instructor at the police academy whose idea of a perfect graduate is someone who salutes on cue and doesn't think or ask questions.

Fortunately the Gen-X Cops have a boss, Eric Tsang, who's that short, fat laughing-stock I was talking about. He's cool, but also (without making a big thing of it) mentally ill. He'll twitch. At one point in the movie he has a nervous breakdown. This makes him more interesting than his apparently predictable story function and gives force to his "challenge the crazy guy" role in the finale.

Anyway, Tsang recruits three dodgy guys who are about to get kicked out of the academy, because he was looking for people who could convincingly go undercover. These are Nicholas Tse, Stephen Fung and Sam Lee, who carry themselves off surprisingly well given that they're all pop stars as well as actors. Lee's playing a character called Alien and is the group's goofball. I liked him best. Fung is the girl-chaser and unfortunately has to do some of it in English, which probably didn't help. Finally Tse is the most important of the three and the only one who was too busy the following year to come back for the sequel. All also do well in the fight scenes, without relying on stuntmen. Oh, and there's also a girl, Grace Yip. She's not a cop, but she shoehorns herself into the group anyway. She doesn't get that much to do, though.

The story that comes from all this is lively. Everyone's the enemy of everyone else, basically. Allies are untrustworthy and hard to find in the first place. Tsang has to jump out of a plane, for instance, while I actually laughed at the scene where the Gen-X Cops have been caught by the bad guys and promptly start fighting each other.

The script is pretty good. Admittedly it bolts on an unrelated third act for the sake of something new to do at the end, but at least the backstory and villains' motivations make sense. Also, more importantly, the comparisons and boundary-crossing between cop and gangster are thought-provoking and yet also make for a cool, exciting film. Anything might happen. It keeps you on your toes. If nothing else, it gives rise to three-way battles in which the police are as liable to get machine-gunned down as anyone. Meanwhile the foreshadowing is slick (um, apart from Act Three), with important story points being set up clearly in scenes that are in themselves cool and entertaining, so never come across as plot-dumps. Look at Grace Yip's Japanese language skills, for instance, or the skydiving.

Don't ask me why those boats exploded, though, or why Toru Nakamura told everyone about the bomb. Those are the only idiot points that jumped out at me, though.

The film's use of language isn't always successful, mind you. It's mostly in Cantonese, but there's plenty of English and Japanese. Most of this is slick and well delivered. Sometimes though an actor simply can't cope with a language, e.g. Nakamura, who's a ghastly actor in English and for no obvious reason is butchering it in a French accent. Other actors though will speak English like a native, but still give performances that are noticeably worse in it. I'm thinking mostly of the romantic material between Fung and Jaymee Ong, although Ong's half-Australian and it's not her who's the problem.

Look out for Jackie Chan's cameo at the end, by the way. Not only is that really him, but the film was produced in association with Jackie Chan Productions. He'd started using his Hollywood pay packets to fund Hong Kong movies starring promising youngsters.

In summary, I enjoyed this a lot. It's a solid action movie with a strong story framework and lots of entertainment value. You've got to love a movie where you genuinely don't know at the end whether our heroes are about to go to prison or rejoin the police force. Meanwhile the plot logic hiccups are few and forgivable, although there are occasional problems with the film's fondness for non-Chinese languages. Apparently even the releases were excellent, with Universe's Hong Kong DVD winning high praise and then Columbia Tristar rolling out the red carpet for the film over here in the West, eschewing the Americanisations that other studios had inflicted on other Asian imports (cutting out footage, changing the music, bare-bones DVDs, etc.). Thoroughly professional. Recommended.

"I'm going to commit suicide at midnight." "No problem, I'll pick you up at 11 pm, then."