Theme throughout of sacrifice made in an immense struggle against evil; a tormented king must send his people to likely death in battle, including kids; Frodo must continue carrying the ring despite the pain it inflicts on him. Talk of mercy and compassion for the grotesque Gollum, understanding the creature despite his treachery. An immortal Elf princess considers choosing love over living forever. Evil forces of the dark wizards equated with industrialization, forest clear-cutting and mechanized development.
Thousands of battle casualties in death by arrows, spears, and swords and one gigantic explosion. Threats of cannibalism. Orcs are dismembered and decapitated and, in once case, apparently devoured by other Orcs (with some gore). Gollum tears up freshly killed rabbits to eat. Hand-to-hand combat and tussling with Gollum. People fall from great heights.
Hard to ignore the original Tolkien books, not to mention a plethora of video games, movie tie-in action figures, role-playing games, plus the movie sequels and other existing adaptations.