To play the Atari Adventure game select it with your mouse cursor and then select GAME RESET. At that point you can play the game using the arrow keys and the space bar to drop the one item you can hold. Use colored keys to get into the castles. To see the full instructions in a new window click here.
The pdf on how to play is here.
This game in the early 80’s inspired me to be a game programmer. It was written in only 4k of code. If you use GAME SELECT to play level 2 or 3 you can find a secret dot that allows you to enter a special room with the authors name. The worlds first Easter Egg:)