In interactive fiction you play the main character of a story. You type commands which determine the actions of the character and the flow of the plot. Some IF games include graphics, but most do not: the imagery is provided courtesy of your imagination. On the other hand, there's a wide range of action available. Whereas in other games you may be restricted to restricted to shooting monsters, moving around, or searching items, IF allows you a wide range of verbs.
Interactive fiction comes in a wide variety of types and genres. There are IF mysteries, thrillers, romances, and science fiction stories. There are games about espionage, games about fighting dragons, games about being a cat burglar or searching an abandoned house for loot. Some pieces are fairly serious and literary, while others are enjoyable romps. You can experiment until you find something that suits your own tastes.
Some IF games are more suited for the beginning player than others. If you would like recommendations, see Fredrik Ramsberg's IF Starter's Kit for some ideas.
Make sure that you have the most up-to-date version of the game available. Playing an older version may mean that you'll run into more bugs and design flaws. Although authors try to create impeccable games, many problems become visible only after the public begins playing. This is especially likely to be an issue if you are playing a game that was submitted into a competition and that you downloaded as part of the competition package.
To find out whether you've got the latest version, check the game's website (if it has one) or Baf's Guide to Interactive Fiction. Baf's Guide lists the most recent versions of every game available on the IF archive and has links to them.
Most IF games are set in a world made up of rooms without internal division. Movement between rooms is possible; movement within a room does not always amount to anything. >WALK OVER TO THE DESK is rarely a useful sort of command. On the other hand, if something is described as being high or out of reach, it is sometimes relevant to stand on an object to increase your height. This kind of activity tends to be important only if prompted by the game text.
Objects in the world of IF are generally conceived of as single, intact units. Occasionally it is possible to break an object and have pieces left over when you're done; much more frequently, however, an item is either there or not there, whole or nonexistent. Sometimes things are listed as having parts-a lever, a button, a screen, a keyboard-but it is usually the case that if you find a tree in IF, you will not be allowed to pull off all the individual leaves. Water tends to come in unitary quantities, and often the author will not let you pour it out of the bottle it came in.
One thing that IF does tend to model thoroughly is containment. Is something in or on something else? The game keeps track of this, and many puzzles have to do with where things are-in the player's possession, lying on the floor of the room, on a table, in a box, etc.
Types of Action
Most of the actions you can perform in the world of IF are brief and specific. >WALK WEST or >OPEN DOOR are likely to be provided. >TAKE A JOURNEY or >BUILD A TABLE are not. Things like >GO TO THE HOTEL are on the borderline: some games allow them, but most do not. In general, abstract, multi-stage behavior usually has to be broken down in order for the game to understand it.
Other characters in IF games are sometimes rather limited. On the other hand, there are also games in which character interaction is the main point of the game. You should be able to estimate a character's importance to a game rather quickly-if they seem to respond to a lot of questions, remember what they're told, move around on their own, etc., then they may be fairly important. they aren't described well, have only a few stock responses that they constantly repeat, or are mostly unresponsive to whatever you do, then they are most likely present either as local color or to provide the solution to a specific puzzle or set of puzzles. Characters in very puzzle-oriented games often have to be bribed, threatened, or cajoled into doing something-giving information or objects, reaching something high, allowing the player into a restricted area, and so on.