First Night: Harry Potter and the Half-Blood Prince, Odeon, Leicester Square

It's dark – but at least there's a kiss

Gone are the happy-go-lucky adventures of young Harry, Ron and Hermione; danger and darkness lie in wait in Harry Potter and the Half-Blood Prince. The books, and correspondingly the films, have graduated in seriousness.

Director David Yates balances this with humour, though, and maintains an air of adolescence. We get a little romance: Harry realises that he fancies his best friend's sister, Ginny, and the pair share a kiss; and the long-awaited romance between Ron and Hermione finally takes shape, albeit awkwardly.

Remember, in this film Harry is supposed to be 16. Neither he, Ron nor Hermione looks 16 – but they don't look ridiculously old; hair and make-up have done their job.

As Ron Weasley, Rupert Grint is hilarious, capturing that feeling of uncomfortable, awkward youth. Even Daniel Radcliffe (Harry) manages to be funny when taking a potion that brings good luck in all his endeavours. Sadly Emma Watson (Hermione Granger) doesn't achieve the same level of humour, but at least she tries.

The acting of all three main characters has stepped up a level: still not great, but it's passable. They are, naturally, shown up by co-stars Helena Bonham Carter, Alan Rickman, Maggie Smith and Jim Broadbent. Only one big name, Michael Gambon, disappoints; he doesn't quite capture the pure love of Albus Dumbledore – at times coming across as too harsh.

The scriptwriters bungled several key set pieces, including the funeral scene – although they almost make up for it with a magical passage where students and teachers raise their wands in tribute. Tears poured down many faces in the cinema at that moment.

The Half-Blood Prince is frightening, funny, romantic and entertaining but as the end credits rolled, I still felt disappointed. I had waited all year to see my second-favourite Potter book brought to life. If I wasn't a die-hard fan, I'm sure I would have loved it. My gripe is that the film was simply too different from the book – the writers inserted pointless scenes and took out others crucial to the narrative.

It just could have been better.