Swords and Serpents can be played by one, two, or four players (by use of the NES Satellite or other 4-player adapter). Control of the characters is divided evenly among the number of players, but one player must be chosen as the party leader to control navigation through the game. Upon starting the game, the player creates a party of four adventurers, choosing one of three available classes for each character: warrior, thief or magician. Character statistics can be randomly generated, or the player can choose a ready-to-play party which includes characters of each class. Gameplay is simple. The player navigates through a crude representation of a dungeon, presented in split-screen format which allows the player to simultaneously view the dungeon from a first-person perspective and a simple map of the current level showing the party's location. Encounters with monsters occur randomly, during which the map is replaced by gauges representing the creatures' health. During fights the player controls the characters' actions to attack, cast magic spells, or flee. The entire game takes place in an underground dungeon composed of 16 levels, with the serpent at the bottom.