Science Fiction, Adventure, Myth
The story is set in the future, so that kind of makes it science fiction by default, complete with high-tech gadgets, strange new social arrangements, and guys in white who bear a suspicious resemblance to Imperial Stormtroopers. That's the great thing about sci-fi: if it's the future, it can look like whatever the creators want. It lets them conjure up specific images and feelings and pretend like it's just another day in the 23rd Century.
Like a lot of sci-fi, it's an adventure story, too. Katniss is whisked off from her mundane home into a new, exciting and very dangerous world far beyond her imagining.
Finally, The Hunger Games wants us to think about this new story in terms of some very old ones, and that means adding a dash of myth into the mix. Author Collins said she intended her books to evoke Greek mythology, to point out how stories set in the future could have the same larger-than-life feeling as stories of gods and monsters do. Interviewing the author, the New York Times writes:
As her primary influence, Collins, who has a love of classical plays, frequently cites the Greek myth of Theseus and the Minotaur, in which the people of Athens are required by their Cretan adversaries to offer up seven boys and seven girls for sacrifice to the deadly Minotaur, a half-human monster who lives in a maze. "I was also heavily influenced by the historical figure Spartacus," she said. "Katniss follows the same arc from slave to gladiator to rebel to face of a war. (Source)
In the film, images evoking the gory glory of Rome are everywhere. The Tribute parade could have been pulled straight from old Roman epic films; Snow speaks to the Tributes from on high like Commodus to the gladiators; the mobs cheer the Tributes they know will be dead in 24 hours; the Capitol sends wild animals into the arena to tear the Tributes apart. Even the grand scale of the Capitol architecture has a Rome-meets-Nazi Germany thing going on. We can't wait to see this new Empire fall.