First half goes from promising to somewhat interesting but loose.
Second half (ok, perhaps last third) goes from not so good to "meh, it ended at last".
The worst of the film comes from the caricaturesque "ultraviolent" (as in The Clockwork Orange) villains in the supporting cast. The film is, also, overedited and searches too much for visual impact than the high tension that it should. The script has some good moments but there are some others where you just can´t believe what is happening (like the way she gets from south spain to germany or how a girl who has just discovered electricity uses internet).
On the good side Saoirse Ronan acts good enough, Blanchett the same (her character is not so good, though) and the premise is fun enough to get you to the end with hope. The best element is Hanna (the character) and you cant help but to hope for another, better, part although you know that just cant exist.
All in all it´s a decent film and a more than interesting way to approach the nearly dead action genre. I came to this film from the Chemical Brothers OST that doesnt work as good as I hoped. The leifmotif-song for the crappy male villain is heard so many times you´ll want to puke.