80's RPG classic

In the game, the player controls a square avatar whose quest is to hunt an open world environment for a hidden magical chalice, returning it to the yellow castle. The game world is also populated by roaming enemies: dragons, which can eat the avatar; and a bat, which randomly steals and hides items around the game world. The player character explores a multi-screen landscape containing castles, mazes, and various rooms, with thirty rooms in all. Hidden throughout the world are a sword, keys that unlock each of the three castles (golden, black, and white), a magic bridge that allows the avatar to travel through barriers, and a magnet that attracts the other items toward it.