The Hitchhiker's Guide to the Galaxy is an interactive fiction video game based on the comedic science fiction series of the same name. It was designed by series creator Douglas Adams and Infocom's Steve Meretzky, and was first released in 1984 for the Apple II, Macintosh, Commodore 64, CP/M, MS-DOS, Amiga, Atari 8-bit family and Atari ST. It is Infocom's fourteenth game.
The game loosely mirrors a portion of the series' plot, representing most of the events in the first book. Arthur Dent wakes up one day to find his house about to be destroyed by a construction crew to make way for a new bypass. His friend Ford Prefect, who is secretly an extraterrestrial, helps to calm Arthur down and hitches them a ride on one of the ships in the approaching Vogon constructor fleet, moments before the fleet destroys the Earth to make way for a new hyperspace bypass.
Aboard the ship, Arthur learns that Ford is a journalist for The Hitchhiker's Guide to the Galaxy and has been on Earth researching the planet for the Guide. The two are discovered by Vogons, and subjected by the captain to a reading of his poetry. The two manage to survive this, and the Vogons instead throw them into the airlock and shoot them out into space. By a huge improbability, they are picked up in the last moments before they die of asphyxiation by the spacecraft, the Heart of Gold while it is traveling on Infinite Improbability Drive. After getting safely aboard the ship, Arthur and Ford meet Ford's friend Zaphod Beeblebrox, who had stolen the Heart of Gold as his first act of office as the Galactic President, and Arthur's friend Trillian (Tricia McMillan), who Zaphod had picked up from a party on Earth. Zaphod wants to travel to the legendary planet of Magrathea, believing it holds a great secret.
At this point, Zaphod leaves the task of getting to Magrathea to the ship's computer Eddie, and he, Ford, and Trillian depart to the ship's sauna. Arthur finds Eddie incapable of getting to Magrathea without help. Arthur initially tries to help by supplying the Infinite Improbability Drive with a tea substitute from the ship's Nutrimatic device to serve as a source of Brownian motion, but this only causes Arthur to temporarily take on the consciousness of Ford, Zaphod, and Trillian in their respective pasts, and must manipulate events such that items in these past periods are brought aboard the Heart of Gold in the present. Through this, Arthur gains enough parts as to replace the circuit board in the Nutrimatic so that it can produce real tea. This tea is powerful enough to power the Drive to get them to Magrathea, but in orbit, the ship is attacked by two missiles from the surface. Arthur employs the Drive again that changes the missiles into a sperm whale and a bowl of petunias, neutralizing the threat.
The ship prepares to land, but the computer will not let them do so. Again, the other three head off to the sauna, leaving Arthur to figure out how to fix this. This requires Arthur to reach Marvin the Paranoid Android's closet on the ship as to get the final tools needed to fix the computer and get it to land. The game ends as Arthur and the others are about to set foot on Magrathea.
The Hitchhiker's Guide is a text adventure game, where the player, in the role of Arthur Dent, solves a number of puzzles to complete various objectives to win the game. This includes collecting and using a number of items within their inventory. The player has a limited variety of commands that they can enter to observe, move about, and interact with the game's world, such as "look", "inventory", "north" (to move north) "take screwdriver", or "put robe on hook". Most commands will advance the game's turn counter, and some puzzles require the player to complete the puzzle within a fixed number of turns or else may end the game and require the player to restart at the beginning or a saved state; passive commands like "look" and "inventory", and mistyped or non-comprehended commands do not count as turns. Once the player can acquire it, the player can use the eponymous Hitchhiker's Guide to the Galaxy to ask about a wide variety of topics, some which may be helpful in solving the game's puzzles.