The plot of 300: March to Glory is the same as the comic book by Frank Miller and the 2007 film, 300. The games time period is shortly before the Battle of Thermopylae. You play as King Leonidus, the protagonist from the movie. Your fight is to defeat the Persians using various hack and slash techniques.
Gameplay is your standard hack n slash fare. The game tries to break up this monotony by including Phalanx Formation, a concept developed in the movie, in which you and your soldiers form an impenetrable wall of shield and spear. Throughout the game you level up your different attributes and eventually gain the ability to dual wield swords.