Every genre has certain basic elements which help define it. If you see horses, ten-gallon hats, and six-shooters, it’s most likely a western. (Or an episode of Firefly.) If there’s huge space-dreadnoughts, starfaring rogues in battered tramp freighters, and mysterious psychic powers, it’s most like a space opera. (Or, er, an episode of Firefly.) If there’s spandex costumes, dramatic speeches, flowing capes, and laser-beam eyes, it’s most likely superheroes (and not an episode of Firefly).
Thematic Elements, Savage Worlds Mars