Zork is a text-based adventure game wherein the player explores the ruins of the Great Underground Empire. The player types text commands for their character to traverse locations, solve puzzles, and collect treasure. The game has hundreds of locations, each with a name and description, and the player's commands interact with the objects, obstacles, and creatures within them. Commands can be one or two words (e.g., "get lamp" or "north") or more complex phrases (e.g., "put the lamp and sword in the case"). The command must fit the location's context (e.g., "get lamp" works only if a lamp is present). The program acts as a narrator, describing to the player their location and the results of certain actions. If the game does not understand the player's commands, it asks for the player to retype their actions. The program's replies are typically in a sarcastic, conversational tone, much as a Game Master would use in leading players in a tabletop role-playing game.

The original 1977 version of the game was a single release, Zork. When it was converted into a commercial software title, it was divided into three episodes, with new and expanded sections added to the latter two episodes. Much of the game world is composed of puzzles that must eventually be solved, such as a set of buttons on a dam or a maze to be traversed.

Zork II: The Wizard of Frobozz is an interactive fiction video game published by Infocom in 1981. It was written by Marc Blank, Dave Lebling, Bruce Daniels and Tim Anderson. It was the second game in the popular Zork trilogy. It begins where Zork I left off and leads into Zork III. It is Infocom's second game. 

The player starts in the Barrow from Zork I armed only with the brass lantern and the elvish sword. The purpose of the game is not initially clear. The Wizard of Frobozz is soon introduced. The wizard was once a good sorcerer, but when his powers began to go away he was exiled by Lord Dimwit Flathead. Now bordering on insanity, the wizard is a force to be reckoned with. Your goal, as you venture into the wizard's area, is to avoid his tricks and learn to control his magic. Like its predecessor, Zork II is essentially a treasure hunt. Unlike the previous game, the ten treasures are tied together by a crude plot. Finding the treasures does not end the game, and finding all the treasures is not needed to finish the game. Instead, the adventurer must figure out a way to use the treasures in order to reach the game's finale. 

ZORK III: The Dungeon Master draws you into the deepest and most mysterious reaches of the Great Underground Empire. Nothing is as it seems. And the one responsible for the shadow and darkness - the Dungeon Master - embodies the greatest mystery of all. in this test of wisdom and courage, you will face countless dangers. But what awaits you at the culmination of your odyssey is well worth risking all.

An old, oddly youthful man turns toward you slowly. His long, silver hair dances about him as a fresh breeze blows. "You have reached the final test, my friend! You are proved clever and powerful, but this is not yet enough! Seek me when you feel yourself worthy!"

Difficulty: Advanced

Zork III, is the last episode set in the original Zork trilogy. 

Twelve hours to solve the mystery. One false move, and the killer strikes again. It's Deadline, and it puts you, the keen-eyed sleuth, against a 12-hour time limit to solve a classic locked-door mystery. Armed only with the clues inside this package and your own wits, you must sift through myriads of evidence and motives to track down the killer. No easy feat, for all six of your suspects exercise free will - coming and going, scheming and maneuvering independently of your actions. Some of these personalities are so treacherous that if you make the wrong move, one may do you in.

Deadline is one of Infocom's most difficult games, and requires a number of playthroughs to win. Important events happen at specific times of day, and you have to know about them and be in the right place at the right time to take advantage. It's easy to miss evidence or misunderstand it. There's limited time to complete your investigation. And, of course, you can ruin everything by arresting the wrong person.

Difficulty: Expert. 

Starcross, Infocom's science fiction mind-bender, launches you headlong into the year 2186 and the depths of space. And not without good reason, for you are destined to rendezvous with a gargantuan starship from the outer fringes of the galaxy, peopled with both harmful and helpful beings. But the great starship serves a far larger purpose than mere cultural exchange. It bears a challenge that was issued eons ago, from light years away - and only you can meet it.

You find yourself on a large cylindrical spaceship of alien origin, with all systems controled by fitting these rods into like-colored slots. You start the game with none, but you need all of them to get to the end. Thus, the main thrust of the game is finding these rods in their various hidden places, and solving the puzzles that keep them from easy acquisition.

Difficulty: Expert

"Join the Patrol, and see the Galaxy!" You took the poster's advice, bait and all, and marched right over to the recruitment station near your home on the backwater planet of Gallium. Images of exotic worlds, strange and colorful aliens, and Deep Space heroism had danced in your head as you signed the dotted line. And since that day the closest you've come to Deep Space heroism was scrubbing down the radioactive leper colony on Ishmael-3.

But suppose that jumbo fortune cookie you got at Qwang's Take-Out Asteroid last shore leave was right. Maybe you will indeed narrowly escape disaster. It's even possible that you'll actually travel to an unknown corner of the Universe, where you'll save a doomed planet - or die in the attempt. In fact, we'll guarantee it - every crumb of it - because that's just the way the cosmic cookie crumbles.

Difficulty: Standard

In Enchanter, the first of a spellbinding series in the tradition of Zork, you are a novice magician whom Fate has chosen to do singlehanded combat with a dark and fierce power. But worldly weapons will avail you naught, for your foe is the Evil Warlock who holds sway over the land.

To defeat him, you will have to match your skills as a necromancer against his, casting spells you have learned from your masters in the Circle of Enchanters and other incantations you will acquire as you proceed on your quest.

If you succeed, you will be elevated to a seat in the illustrious Circle; if you fail, your land will be doomed to an eternity of darkness.

Difficulty: Standard.

Infidel finds you marooned by your followers in the heart of the deadly Egyptian Desert. A soldier of fortune by trade, you've come hither in search of a great lost pyramid and its untold riches. Now, alone, you must locate and gain entry to the tomb, decipher its hieroglyphics and unravel its mysteries one by one.

Through the Antechamber, the Barge Room, the Chamber of Ra, death will lick at your heels as you race to the shattering climax of this match of wits between you and the most ingenious architects, builders and murderers of all time - the ancient Egyptians.

Difficulty: Advanced

Sorcerer, the second of a spellbinding fantasy series in the tradition of Zork, takes you on a magical tour through the darker side of Zorkian enchantment. Your journey begins with a cryptic diary - the last trace of the now-vanished Belboz the Necromancer, grand and powerful leader of the Guild of Enchanters. It is feared that Belboz is in thrall to evil sorcery. If so, the very existence of the Circle of Enchanters could be forfeit. To rescue the kingdom and locate your mentor in the treacherous mists of time, you must gain the power and cunning of a true Sorcerer.

Sorcerer is the "middle child" of the Enchanter trilogy, and like many middle installments, it tries to go beyond the old game into new territory while developing some aspects. This game is still focused on scrolls, but it adds potions and many more Zorkian pick-up-and-carry-around items. Many items are items from MIT Zork which have been repurposed. 

Difficulty: Advanced

Don't Panic! Relax, because everything you need to know about playing The Hitchhiker's Guide to the Galaxy is contained in the pages of this manual. In this story, you will be Arthur Dent, a rather ordinary earth creature who gets swept up in a whirlwind of interstellar adventures almost beyond comprehension. As the story begins bulldozers are waiting to reduce your house to rubble to make way for a motorway bypass. While you attempt to deal with this problem, your rather strange friend Ford Prefect drops by to tell you that the Earth is about to be demolished to make way for an interstellar bypass! If you survive this double threat, you'll embark on a series of inter-galactic misadventures even funnier than your worst nightmares!

A special note for people who have read the book "The Hitchhiker's Guide to the Galaxy". Although the opening of the game is fairly similar to the book, the story quickly diverges, with lots of new material and different twists. Although familiarity with the story may make a few of the early puzzles easier, if you rely too heavily on this previous knowledge you will certainly end up getting misled.

It's an ordinary day in your ordinary little town, and you've been performing your ordinary mail clerk's duties in an altogether ordinary way. But there's something quite extraordinary in today's mail. It's a ransom note for a kidnapped cat, and it will lead you through unbelievably harrowing adventures to Wishbringer, a stone possessing undreamt-of powers. For though the note in question is addressed to someone in your ordinary little town, it's postmarked for Special Delivery to Parts Unknown. And its true destination is somewhere beyond your wildest dreams, c/o the magic of Infocom's interactive fiction.

Wishbringer was part of Infocom's "introductory" line -- an attempt to bring a wider audience to interactive fiction by creating works that would appeal to those who had never played a text adventure before. Only a few introductory titles were produced, and this one is my favorite by far.

Difficulty: Introductory

Following the events on Resida in Planetfall, the player's character received a promotion from lowly Ensign Seventh Class to Lieutenant First Class. The life of an officer in the Stellar Patrol is no better than that of a humble enlistee, however. Five years after the thrills of saving an entire planet from destruction, the character is stuck in a boring desk job that demands piles of tedious paperwork instead of menial cleaning duties.

A typically boring assignment comes in: accompany a spacetruck to a space station and pick up a load of "Request for Stellar Patrol Issue Regulation Black Form Binders Request Form Forms". To make things even more dull, spacetrucks are fully automated, so it will pilot itself once the proper coordinates are entered.

But the task does authorize the use of a robot assistant, and coincidentally enough, Floyd, a beloved companion revived at the end of Planetfall, is one of the choices.