If I were to classify it as anything, I'd say its a comedy. A highly sophisticated and subtle comedy, but certainly a comedy, possibly one of the greatest ever made. First half a satire of American life in the 70s of a culture, a culture that was trying to flee from the horrors of the Vietnam War it experienced just years before and live in denial; and the second half a violent, disturbing parody of z-grade monster flicks and Hollywood machismo and dick-waving.