A UI presents a structure to enable the user to query and manipulate objects. A CLI represents that structure by accepting textual commands and presenting outp

A UI presents a structure to enable the user to query and manipulate objects. A CLI represents that structure by accepting textual commands and presenting output textually. A GUI represents that structure by displaying objects graphically, showing their spatial representation and connection. And, traditionally, a GUI tends to show more structure up front while a CLI simply prompts you for a command. The distinction isn't perfect, but a text adventure game is well inside the CLI camp.