Kingdom Under Fire included single-player and multiplayer online modes through Phantagram's "Wargate" server. The game is the first release in the Kingdom Under Fire series which later received critical acclaim through the Xbox release Kingdom Under Fire: The Crusaders, a game which, like others in the series, incorporated both role-playing and real-time strategy elements. A "Gold Patch" was released for Kingdom Under Fire which introduced a map editor, extra missions, and in-game save option; the version was also re-released as Kingdom Under Fire Gold.
Two factions, light and dark, are playable in the game, with each side having units fulfilling the typical roles of warrior, archer, flying unit and wizards – as well as more powerful individual hero characters. The campaigns are split into 13 missions of which 10 are battles and the other three being a dungeon crawl for a hero character. Skirmish and multiplayer modes were also supported, with online games with human opponents organized via the Wargate.Net server.
