Which are the main differences between Fahrenheit 451 novel and its graphic novel?

Bradbury was involved in Tim Hamilton's adaptation of Fahrenheit 451, so in plot and the "feel" of the drawings the graphic novel is faithful to the original work. The main differences are the necessary condensation—as critics have noted, graphic novels tend to take books and turn them into "scripts" that rely on dialogue. Hamilton does this, removing much of the interiority of the novel. Second, we lose most of Bradbury's lyrical, imagistic prose. The graphic novel is much more spare in its language: it is a rewrite. For this reason, although Hamilton's images are compelling, I believe the "translation" across genres loses something important. Clarisse, for example, turns from an ethereal amethyst and milk-white teenaged waif who represents poetry and nature into a somewhat sexy woman who questions Montag, but doesn't necessarily stir him to think about society and his role in it.
Likewise, we lose such details as Montag's introspective examination of his alienation from Mildred and his yearning to overcome it, and his introspective epiphany at the end that fire can warm (be put to good use) and not just burn (destroy). In general, the graphic novel is a good rendition of the plot (action) elements of the novel but loses some of the crucial interiority and lyricism of the original. This is not meant to slam the graphic version, but to point out how genres change emphases and sometimes lose crucial pieces of an original.