While it's true that movies can't be word for word translations of books, nor image by image, they can still be true to the story. The only reason stories (I'm using that as a very broad term) are made into films is because the story invoked passion of some kind in its readers. Too often, Hollywood either doesn't understand what passions were invoked in the reader, how to translate those to film, or dismisses them entirely. However, oftentimes a story is far too complex, contains too many character, too many divergent plot lines, or too many ideas for a proper translation to occur. When that happens, we either find a script that cuts to the core of the story and eliminates anything that isn't absolutely essential to the story. That's where everybody has difficulty. Hollywood and the fans of the story rarely agree on what was left out, what was left in, what was enhanced - what was essential.
It seems, according to reviews here, that the film remained essentially true to its core, and trimmed around the edges. That said, many here disagree vehemently.
That served me fine. I didn't find gaping holes or questions, and never felt that any plot line was hurried. The film presented radical ideas in a magnificent fashion, first through a very unlikely hero (whose creation was, as usual, tragic), and second through the establishment he was fighting against.
"V" was pursuing two things in the film. 1) To bring down the establishment, which had become increasingly totalitarian, and 2) to make those responsible for his creation pay.
Both are radical, subversive, and vigilante in nature. Some have said that "V" is a terrorist, and in a sense, he certainly is. This is no Batman, no Spider-Man, and certainly no Superman. He is not a crusader for good, and possesses his own set of ethics - undoubtedly burned into him in his birth. While I personally can't agree with his tactics, I never found myself rooting against him. The "system" that was in place was a horrid one, and it did need to be brought down - especially by someone who himself had been "brought down" by the system.
The acting is first rate, as are the special effects.
As I noted in the first paragraph, stories are made into film because the story invoked passion of some sort. This film certainly evoked passion in me. It's a terrifying reminder that totalitarian regimes have existed, that some have been created virtually overnight, and how perilously close we are now to slipping backward, instead of forward.