itch.io

Focused on imparting a skill, lesson, or piece of information to its player that would be helpful to them in other aspects of life, such as a faster typing ability or knowledge about a period in history.

Taking place after a huge catastrophe (eg. man made or natural disaster). See also the more political theme dystopian.

Focused on using its text, moreso than its visuals or audio, to tell the bulk of its story/plot. (Still can have great audio and visuals, though!)