The premise of this screenplay is the same as comic. In the near future, Britain is ruled by a fascist regime called Norsefire. A mysterious figure, known only as V, challenges the government, espousing the ideas of Freedom and Liberty. V simultaneously avenges himself on the people responsible for forcibly experimenting on him, and topples down the regime that allowed it to happen. Though the majority of the characters from the comic appear here (Conrad and Helen Heyer are the only significant characters not to appear in this screenplay), and several plot elements are duplicated (Evey's near rape, Storm Saxon, etc.), the tone of the adaptation is radically different.
For one thing, the script is that it can't decide if its straight drama or satire. In the very first scene, we are treated to tongue-in-cheek radio commercials for genetic engineering and news regarding "IBM-Chrysler" (capitalism existing in a fascist state is just one of the script's incongruities). The headquarters of Norsefire's government are in the shape of their namesakes: The Nose's building is a huge nose, The Ear's building is indeed an ear, etc. Bishop Lilliman presides over an surreal religion that is literally one part Catholicism and one part airplane safety-demonstration. And, in the most striking visual, Norsfire's Fingermen are genetically engineered half-man/half-goat creatures.
Things become in more incongruous given that so much of the story is played straight: V dispatches Prothero much the same way as the comic. Finch undergoes his epiphanies, Evey is captured and tortured (though in this version it truly is Norsefire who is responsible), V confronts Deliah, Rosemary is driven to assassination. It is a weighty script. But it fails to balance the absurd elements with the dramatic ones because the absurdities are never given any context. Why there are Goatmen? Why is The Finger's headquarters is shaped like a finger? If the absurdity came from the characters, we could see the individual personalities balance themselves between the absurd and the dramatic; instead the absurd becomes window dressing, and juxtaposes poorly with the dramatic personalities that are surrounded by it.
This said, in some ways the screenplay tries to correct shortcomings of the comic. Much more attention is given to the "everyman" of Vendetta's world. In the comic, the faceless masses very much remain faceless masses, save for an occasional glimpse. Though in some ways their lives are presented in absurdist extremes--the script describes their living conditions as if society reverted to the 1860's--we do see, in detail, the way the populace lives, and, perhaps more importantly, how much they are inspired by V's crusade. There s a more active Resistance army and we repeatedly see their own struggle against Norsefire.
Furthermore, the relationship between Susan and Fate is given greater attention. Fate is given an actual, feminine, voice, and the relationship between the two becomes surprisingly intimate. On paper it reads rather silly, but if handled with the right touch, it could actually work.
V's character is also handled differently. In the comic, as appealing and admirable as V is, he is a non-entity. Beyond his purpose to the plot, he has no feelings, no thoughts. He is the physical embodiment of his ideals, which are admirable, and his struggle is identifiable, but ideals do not make a character three-dimensional. The script addresses this problem by trying to humanize V. He is shown to be a far more eccentric personality, more personable, and more emotional. He actually breaks down and cries when he confronts Deliah, and later on when he recounts his torture at Larkhill. He is shown hesitating at the end, experiencing a moment of doubt at the end when he needs to go to his confrontation with Finch. At the end of the script, V is revealed to indeed be Evey's father, giving a true face behind his mask.
These are radical changes and I can understand why they are made. The audience needs to connect with V; this is a movie meant to play across the nation and not in a few art-house cinemas here and there. For this to happen V, as the protagonist, has to be a character. But, ultimately, the script is not successful in its attempt. V's relationship with Evey comes across forced and clichéd. (Though this could also be due to the poor characterization of Evey herself.) What's more, V's philosophical doctrine is a watered-down version of what appears in the comic. He espouses the ideas of happiness and liberty but they are only paid lip-service because no serious discourse on the concepts takes place. In the end, V becomes just another vigilante "fighting against The System." Though eccentric, he is ultimately generic.
It's an interesting adaptation that certainly tries to put its own spin on the story. Though hardcore Vendetta fans may dislike it for its difference to the comic, the script does remain true to the comics spirit, even if it collapses under the weight of too many ideas and not enough exploration of them.