Her Knights: All for the Princess is a spin-off of Geunyeo-ui Gisadan - Her Knights. Princess Lemian is forced to marry a man she does not love. As she tries to escape from the unwanted wedding, she realizes that her path is blocked by soldiers. Her faithful knights arrive to fight them and help the princess escape.

Unlike the preceding game, All for the Princess is a 2D side-scrolling beat-em-up. The player can choose to control any of the five available knights. There are too basic attacks - fast and strong. Combo attacks can be performing by combining these two with directional buttons. There are separate controls assigned to blocking ans evasive manoeuvres. The knights can also strafe backwards, while turning around is performed by pressing a separate button. Enemies usually drop health-restoring or stat-enhancing items when defeated.