Zork I

The faint-of-heart need not apply!
As for the dauntless, prepare to encounter the unknown. The long-abandoned Great Underground Empire — a fantastic realm of magic and mystery — is yours for the exploring.
Abandoned, yes — but the Empire is not totally uninhabited. Still lurking in its crags and crevices are numerous creatures with whom you must match wits, skill and bravery — a thief, a troll and other troglodytes of equally ill repute. Your survival depends on how successfully you vie with these denizens and solve the subterranean world's manifold puzzles. But before you can truly emerge victorious from the cavernous quarters of Zork, you must collect its many priceless treasures and safely bear them to daylight.
Courage, cunning and logic. You will need them all to triumph. The Great Underground Empire awaits. We dare you to enter it!