From the introduction:
When you first start up Super Mario Bros, the game doesn't give you any instructions. The first level is cunningly designed to teach you the rules: jump on enemies, pick up mushrooms, look for secrets, get coins, avoid pits. There is no tutorial. The game itself is the tutorial.
This dungeon is designed to take a group of non- gamers - even non-video-gamers - and teach them the basics of dungeoneering.