Swords & Serpents is a one or two player Dungeons & Dragons-style dungeon crawl. In a one-player game, the player controls the Warrior Prince on his quest to collect treasures, learn the secrets of the Fortress of the Sinister Serpent, and locate the Serpent's lair. In a two-player game, the right player controls the Warrior Prince, while the left player controls Nilrem the Wizard.
As players explore the labyrinthine fortress they can collect treasures, magic scrolls, and healing items while battling Phantom Knights and Red Sorcerers. But they must be careful—if their adversaries catch them, they can lose half a life, and may need to be "reincarnated." Each player has only 9 Reincarnations, and when those are gone, the game is over.