I've posted these comments here because some of you may be intending to see the movie and not want to know beforehand what happens in it !
Anthony Horowitz wrote the screenplay to the movie of his book, Stormbreaker, and I would say he's done the job of adapting the book for the screen pretty well. I enjoyed this movie quite a lot; I thought Horowitz got all the major plot points in and then developed it into a fast paced movie. The only thing I really disliked was the "cat fight" between Frau Vole and Jack Starbright - it was far, far too silly.
There were some excellent stunts and special effects, and I felt Alex Pettyfer did a good job of playing Alex Rider - it's just a shame he won't be working on the next film; since Alex Rider is still 14 and Alex Pettyfer is now 16, they will replace the actor in a rather Bondesque manner !
It was interesting (but unsurprising) to see Alex's games device was updated to a Nintendo DS (I believe it was a Gameboy in the book) since the boy he was supposed to be was a computer geek - therefore it made sense for him to have the very latest games device. I loved the fact that Alex got pretty much all the gadgets that were in the book (from what I recall - it's been several months since I read the book) - and his walking-down-the-wall with the aid of the yo-yo was an awesome stunt.
Andy Serkis was incredibly menacing - far scarier as Mr Grin than he was as Gollum - the very fact that he didn't have a single line of dialogue just added to the menace, I felt ! Bill Nighy was delightfully nasty and unemotional - just how I saw Alan Blunt; also totally clueless (Talking to Mrs Jones about Alex: "Take him for an ice cream. He deserves a treat" !), and Mickey Rourke was just as slimey as he should have been !
I would have liked to have seen more of the characters played by Stephen Fry and Robbie Coltrane (and Ewan McGregor if it comes to that) - just because they're great actors and watching them never seems dull !
Sabina Pleasure had very little to do, unsurprisingly since the character isn't even in the first book (but of course Alex had to have a girl, as a "junior Bond" character).
This is a stonking good film that I am sure will storm (ho, ho !) up the blockbuster charts and give Captain Jack and his Pirates a run for their money...