Genres
LitRPG
Fiction in which the game mechanics are explicit and visible: stat blocks, level-ups, skill trees, status screens.
LitRPG is fiction in which a role-playing game's mechanics are explicit and visible on the page: stat blocks, level-ups, skill trees, and status-screen notifications. The load-bearing convention is that growth must be measurable, not just narrated; when the protagonist advances, the reader sees the system say so.
The label overlaps with the broader umbrella GameLit, and communities apply the two in overlapping rather than strictly hierarchical ways. All LitRPG counts as progression fantasy; not all progression fantasy is LitRPG.
See how to write LitRPG.