Mastery
Also said as Skill mastery, Competence
Getting really good at something, and being able to see that you have. The challenge stays still and you are the one who changes.
It is the most lasting reward a game can offer, and it costs nothing to supply. Games that can support years of improvement keep their players for years, provided improvement is something they can see.
Say it
“Show the player a ghost of their best run from the second attempt on, and their time on every room. Don't add upgrades here: getting faster is the reward.”
Where you’ve seen it
In December 2023, a 13-year-old called Willis Gibson played the 1989 NES Tetris until it crashed at level 157, the first person known to do so. The game had stayed exactly the same for 34 years, and the players had kept getting better.
Not to be confused with progression
Progression gives your character more. Mastery gives you more. Take every upgrade away and your mastery is still there.