What is IF?
Interactive fiction (IF) games played on the computer, often (but not always) text-based, with some interactive element. The most common types of IF are parser games (the player types in commands to make things happen, like "unlock door with key") and choice-based games (the player chooses from various options written by the developers). There's more professionally developed interactive fiction than most people think: Citizen Sleeper, Telltale games, and Scarlet Hollow, and visual novels are all interactive fiction. Some people would argue that Disco Elysium counts.
The IF community
There's also a small but very active community of amateur interactive fiction creators. Fun, creative, thoughtful games are being made all the time just because creators love making and sharing games. Some are all text, some have images, graphics, or animation. IF games come in all sorts of forms and genres: story-driven games, games that simulate combat or resource management, classic puzzle games, and more literary or artistic games don't fit neatly into any one genre.
Playing and making IF
Here are some games to play or tools to make your own:
Playing IF
Repeat the Ending - Summary
Eikas - A choice-based game in which you run a community kitchen in a fantasy world. Has some multiple mechanics-- shopping, cooking, inventory.
Making IF
It's intimidating! While many programs make the process a lot easier (you don't even have to know any html to make and publish an IF game), unless you learn computery things quickly or have experience it can be incredibly overwhelming. Playing IF does help; seeing what other people have done can give you a more specific idea of what's even possible and what questions to ask. Having a story that you want to tell can also help you decide what kinds of interactive elements you want to include.
We've put together a quick list of tools and resources we used to get started. (And still use; learning never ends!) here.