Zork I

Zork: The Great Underground Empire - Part I, also known as Zork I, is an interactive fiction video game written by Marc Blank, Dave Lebling, Bruce Daniels and Tim Anderson and published by Infocom in 1980. It was the first game in the popular Zork trilogy and was released for a wide range of computer systems, followed by "Zork II" and "Zork III". It was Infocom's first game, and sold more than 400,000 copies.
Plot.
The player steps into the role of an "adventurer". The game begins near a white house in a small, self-contained area. Although the player is not given any instructions, the house is point of interest.
When the player enters the house through a window, it yields a number of interesting objects: an ancient brass lantern, an empty trophy case, an intricately engraved sword, etc. Beneath a rug a trap door leads down into a dark cellar. But what appears the cellar is actually one of several entrances to an underground area—the Great Underground Empire. The player soon encounters dangerous creatures, including deadly grues, an axe-wielding troll, a giant cyclops and a nimble-fingered thief. 
The goal of "Zork I" is to collect the Twenty Treasures of Zork and place them in the trophy case. Finding the treasures requires solving a variety of puzzles such as the navigation of two difficult mazes and some precise controls at Flood Control Dam #3. 
Placing all of the treasures into the trophy case scores the player 350 points and grants the rank of "Master Adventurer." An ancient map with further instructions then appears in the trophy case. These instructions provide access to a stone barrow. The entrance to the barrow is the end of "Zork I" and the beginning of "Zork II".
It is possible to score all 350 points in 223 moves (and win the game completely in 228 moves) by exploiting a bug.