The box office is almost never a good way to gauge the quality of a movie, but sometimes it gets it completely right. Where The Muppets was a funny, honest labour of love from a creative team who wanted to do it justice and made plenty of money as a result, Muppets Most Wanted is a lazy cash-in by a studio only interested in pushing product, and audiences consequently told Disney what they thought.

It also makes the age-old Crocodile Dundee mistake – the original film was about The Muppets themselves and what they do best, the same way Paul Hogan's Mick Dundee was such a distinctive character he was the movie.

But for the sequel, they've tried to expand the remit by putting the unique characterisations in a crime caper, and all it's done is overshadow what they do best. It's probably the same reason no other film in the original franchise worked as much as The Muppet Movie.

When slimy entertainment agent Derek Badguy (Ricky Gervais) convinces the Muppets they should tour Europe, he's really the henchman for renowned jewel thief Constantine, the most dangerous frog in the world – who happens to look just like Kermit except for a mole on his cheek. When Constantine and Badguy conspire to have Kermit thrown in a Russian gulag and replace him with Constantine, the tour follows the path they need to make the ultimate score – stealing the crown jewels from the Tower of London.

Even though Constantine does a terrible impression of Kermit, he and Badguy have everybody fooled while the real Kermit is locked away. He's left trying to form alliances with the inmates of the prison camp (including Jemaine Clement and Ray Liotta) and get on the good side of the vicious commandant (Tina Fey), putting on a revue as a cover for his escape.

It's not clear if the movie isn't working because the story wrong-foots you from the outset or not, or whether it's just not as funny. The cameos are fun but the musical numbers just grate this time around and the bland plot isn't enough to have much fun with.

A couple of elements stand out – like Sam the Eagle and a French detective (Ty Burrell) trying to one-up each other's performance – but it's not a patch on the first film.