Swordquest: Earthworld was the first in a series of four puzzle adventures for the Atari 2600, the last of which, Swordquest: Airworld, was never released. In Earthworld you have 12 rooms to explore, one for each sign of the zodiac. Gameplay consists of collecting objects and placing them in their proper room. When an object is correctly placed, it reveals a clue that may:
"1. Refer back to the enclosed comic book and hint at the solution to the Earthworld puzzle.
2. Refer to the next world in the Swordquest series, Fireworld.
3. Help you solve the final puzzle of all four Swordquest cartridges combined."
Scattered throughout the game are "skill and action tests," which are mini-games that when completed successfully will reward you with an "object that will work great enchantment for you."
Once you have completed all tasks and placed all 15 objects correctly, the game is over and you receive a final clue for use in Swordquest: Fireworld.