The player's goal is simply to find the enchanted chalice and return it to the gold castle. The player character, represented by a square, explores a multi-screen landscape containing castles, mazes, and various rooms. Hidden throughout the world are a sword, keys to unlock each of the three castles (gold, black, and white), a magic bridge which allows the player to travel through a wall, and a magnet which will pull any of these objects toward it.
Roaming the world are three dragons:
Yorgle, the yellow dragon: He is afraid of the golden key and will run away from it. He guards the chalice when he can find it; otherwise he wanders around or helps the other dragons guard their possessions.
Grundle, the green dragon: He guards the magnet, the bridge, the black key, and the chalice.
Rhindle, the red dragon: He is the fastest of the three and the most aggressive. He guards the white key and chalice.
Here the player (top right) is carrying the Sword, and Rhindle (middle) is guarding the chalice (left).
A dragon can be "killed" by touching it with the sword. If the console's right difficulty switch is in the "A" position, the dragons will run away when they see the sword.
When a dragon touches the player, it will "strike" (remaining motionless for a moment with its mouth open, waiting for a shorter time if the console's left difficulty switch is in the "A" position) and then "swallow" the player, who becomes trapped in the dragon's belly. While the dragon's mouth is opened, it cannot be killed.
A black bat flies around randomly, occasionally picking up or dropping objects (including live or dead dragons). The bat can steal the player's sword and give him a live dragon in return, or vice-versa. The player can catch the bat and carry it around. The bat continues to fly even after the player has been killed, and occasionally the bat will pick up the dragon whose stomach contains the player, giving the player a whirlwind tour of the Adventure universe. The player can trap the bat inside a castle; this works best with the gold castle, since it has only one room and (provided the player has emptied it beforehand) the bat will, if it is flying upwards (straight up or diagonally up-right or up-left), fly around endlessly in the room and will not leave the castle. If the player enters with another item, the bat will change direction to grab the new item and usually end up leaving the castle. The bat's name was intended to be Knubberrub, but that name never made it into the manual.[7]
There are three different games available via the Game Select switch:
Game 1 is a simplified version of the game and does not have the red dragon, the bat, the catacombs, the white castle, or the maze inside the black castle.
Game 2 is the full version, having all the features described. The location of the objects at the start of a new game is always the same and because of this known initial state, this is the easiest game to use to find the Easter egg.
Game 3 is just like Game 2; however, the initial locations of the objects are pseudo-randomized, providing a different game each time. Because of this, the game could be easier or harder to solve (occasionally impossible, due to a bug in the item-placement routine that sometimes locks the gold key inside the gold castle). Due to the unpredictable placement of the items, it is more difficult to secure the bat and locate the items needed to find the Easter egg (though the location of the dot is consistent).
When a player is eaten by a dragon, he does not necessarily have to start over. Hitting the "Game Reset" switch resurrects the player back at the gold castle and resurrects any killed dragons; however, the objects all remain where they were at the time of the player's death. This could be thought of as one of the earliest usages of the "continue game" feature, which is now prevalent in most video games. Hitting "Game Select" after death returns the game to the game select screen and an entirely new game can be played.