Faxanadu (Nintendo NES)

You are the elves' last hope. Outside the town walls lurk monsters with the power to destroy anything in their path. Inside the walls, water and time are running out. Soon the ancient elf town of Eolis will vanish into eternity. Only you can save Eolis. No one else dares to venture beyond the walls, onto the World Tree, where towns and fortresses precariously await the whims of fate at the hands of the Evil. You are searching for the water source and for an antidote to the poison that makes the water undrinkable. To find them you'll need gold and food and magic, speed with a sword... and luck. Every town holds a new mystery, every fortress a new danger. Merchants will sell you magic and valuable tools, but it's up to you to figure out what you need. Long, secret mantras help you slip through the mists, but will you survive the next challenge? This is Faxanadu, the legend, the adventure - the incredible journey on the World Tree!