Action

There are a lot of fast-paced action sequences in this film. There's the opening battle scene in Germania, there's Maximus small battle with his would-be executioners, two big gladiator fights in Africa, two big gladiator fights in Rome, another battle at the gladiator barracks, Maximus' attempted escape, and then a final showdown between Maximus and Commodus that Maximus wins despite being injured.

Sure, there's lot of down time—behind the scenes politicking, if you will—but there's no way this film can't be considered an action juggernaut.

Drama

It's during all that down time we just mentioned that all sorts of drama takes place. Commodus' plotting with a senator to make his enemies come to him, Maximus' conversation with Senator Gracchus, Proximo and Maximus' discussions about the nature of gladiatorial entertainment—these are hallmarks of dramatic films.

There's not a lot of humor, and we know that even when people aren't fighting, there's still an immense amount of conflict going on.

Romance

Yep. We went there. And no—we're not talking about Commodus' romantic feelings toward his sister. (Gross.)

Maximus' entire life after about the fortieth minute in the film is somehow avenging his wife's death. He slaughters people in the arenas like it's nothing, and ultimately decides that he'll kill Commodus. After that he doesn't care, and at times we feel like he just wants to die. In fact, this is why he's found by the slave caravan initially: he's essentially resigned himself to death because life without his wife and son just isn't worth it to him.

Sword-and-Sandal

Sword-and-sandal is a catchall term to describe really just about any movie about Ancient Rome, Ancient Greece, Ancient Persia, etc.

These films are called sword-and-sandal films because…they feature swords and sandals prominently. (Who'd have thunk it?) Now, there aren't a lot of other requirements for a film to qualify as a sword-and-sandal film other than that it feature swords, sandals, the ancient world, and dudes running around in loincloths and togas. (Source)