Interactive fiction, also known as text adventure or simply IF, is one of the oldest kinds of computer games in existence. As graphics are limited or, in most cases, completely absent, the game is controlled entirely by text input. The computer uses text to describe important geography, characters, and items. You control the player character by typing a simple text command, then pressing the enter or return key. The computer will do its best to understand your intentions and respond accordingly. To get you started, here's an example of a playthrough of a very simple IF game. Text output by the computer is yellow, and text input by the player is blue:
ESCAPE FROM ORTHERALE CAVERN
Revision 88 / Serial number 423021
You are standing in a dark, dingy cavern. It is too dark to see anything.
-The 1983 Academy Award for Best Supporting Actress
It's too dark to see, but you feel around it for a while until you come to the conclusion that it's one of those lamps you fill with lamp oil then turn on with a switch.
>pour lamp oil into lamp
It's difficult in the dark, but you manage to get most of the lamp oil into the lamp. A bit spilled onto the floor, but whatever.
>turn on lamp
You turn on the lamp and gaze in wonder at the now visible cavern.
It's full of cool stalactites and stalagmites. There is also a rope on the ground. To the north is a slope leading upward.
>look at rope
It's a lasso left behind by a cowboy. Judging by the fibers, the rope seems to be from the early 1800s. That cowboy won't be needing this anymore.
This room's very pretty. Looks like it's covered with crystals and junk. You see light coming from a hole atop a cliff, but it's too high for you to reach.
The poor cliff only has one stalagmite to call its own.
>use lasso with stalagmite
You throw the lasso around the stalagmite. The rest of the rope dangles down the cliff.
You climb up the rope. The exit is in sight! The only problem is a ferocious Skranmos is blocking you! Hurry! Slay it before it eats you!
How? You're very weak. You can't be that vague.
The Skranmos is quickly approaching. He's only a few feet away!
>throw lamp at skranmos
The Skranmos is consumed in flames! It shrieks horribly as it burns to a crisp.
Congratulations! You've made it out of the cave! You win!
You've scored 8 points out of a total 250. Play again? [Y/N]
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