In Adventure, the player (represented by a small square) explores a world consisting of mazes and castles. The world is populated by three dragons which will chase the player, and several items which the player may pick up and use. Items include:
- keys, used to unlock the castles,
- an arrow, used to slay the dragons,
- a bridge, used to pass through maze walls,
- a magnet, used to pull other items toward you, and
- a chalice.
The player may only carry one item at a time. The game ends (and the player wins) when the chalice is returned to the starting castle.
The game is notable for being the first action-adventure game, and containing the first widely known "easter egg" in video game history--a secret item which when found and brought to a particular room displayed the name of the game's designer and programmer, Warren Robinett.
The game features three difficulty settings, which change the distribution of dragons and items and the layout of the map.