I liked this film and together with my 12 years old daughter we spend a nice moment watching it. It is however definitely not recommended to little children, like 10 and younger. This review contains limited SPOILERS.
This retelling of old tale of Jack and the Beanstalk is pretty well done, with many key ingredients of fairy tales well in place. There is a brave and ultimately quite clever farm boy (Jack), a cute and quite likeable damsel in distress, a noble king, his brave knights, a vilainous treacherous scoundrel, powerful magic items, a really REALLY BAD giant alpha (and beta) and a whole batallion of other giants, almost as dangerous as their two-headed leader.
Past the first 10 minutes, the film is rather quick paced and visually it is very pleasant: the sky domain of giants, the giant beanstalks and the mighty royal fortress are really impressive. The desperate fight of royal army against the giants besieging the great royal castle is a particularly well done thing - I certainly appreciated that both humans and giants fight in a rather logical way and human army is definitely not a push-over...
The best character in the film and a scene stealer is Elmont, a sarcastic noble knight commanding royal guard, played very VERY convincingly by Ewan McGregor who seizes this occasion to remind the public, that he once played Obi-wan Kenobi and that after all he killed Darth Maul and General Grievous and defeated and mutilated Darth Vader... Frankly, I almost expected Elmont to finally use his light-saber and I was very surprised when he didn't...
Stanley Tucci who plays the main villain Roderick is another scene stealer, with his quasi Monty Pythonesque style - it is clear he had tons of fun playing in this film. Ewan Bremer, who plays his slightly deranged murderous sidekick Wicke, is another delight to watch.
Compared to those three characters and to all the gallery of giants, both Jack and the Princess seem a little pale - this is the reason I give this film only four stars instead of five.
Children younger than 11 can find this film TOO SCARY, as there are numerous scenes when giants EAT PEOPLE - and even if there is no gore and everything happens fast and is shown in some distance, the scenes are explicit enough to leave no doubt that a character had just his head and shoulders ripped of the rest of his body and swallowed by a enormous, ugly, very strong, very fast and very agressive monster.
But bottom line, I liked this film and I spend a good moment watching it - and I think we will buy the DVD when it is available. Although not a masterpiece, this is a nice, easy, visually very impressive film.