Gunlord is a run and gun game reminiscent of Turrican where players assume the role of Gordian Gaiden across nine non-linear stages set in the planet Kairos II. Its plot takes place after the events of Last Hope, where the evil empire was destroyed by pilot Vanessa Gaiden and although she escaped, her victory was short-lived as she never made it home and was declared missing in action. Meanwhile, a new evil appeared and began to terrorize the galaxy, a planet lord called "The Master" that can create beings of steel and enslave humans by absorbing their souls. Gordian, Vanessa's newlywed husband, is out to search for her when he feels the presence of evil and dons his Gunlord suit.

During gameplay, the player must explore each large and branching stage using abilities such as a morph-ball function like Metroid to find new weapons, of which there are seven weapon types in total, crystals for points and power-up items to upgrade each weapon while fighting against enemies and bosses. In addition to the main platforming segments, there is also a shoot 'em up segment similar to R-Type. The title includes two game modes; arcade and original.