The Lost Kingdom by nanochess is an adventure game made for the Atari 2600.
The story of the game follows about a kingdom, which is in great despair since the king disappeared. The legend says that the crown is hidden somewhere in your world, maybe if you can find it, you can become the king. The objective of the game is simple: explore the world, find the crown, become the king. There are no enemies in this game. Move the peasant with the joystick directions. To take objects you simply pass over them. You cannot go to certain places if you don’t have the right object.
The Assembler source code of the game is freely available.