Skill floor and ceiling
Also said as Low floor, high ceiling, Easy to learn, hard to master
The floor is the least skill you need to do anything at all. The ceiling is the most skill the game can reward. The two can be moved separately.
A high floor keeps beginners out. A low ceiling makes experts leave. Games with a long life tend to have a low floor and a high ceiling, and they do it by rewarding precision without demanding it.
Say it
“Keep the floor low: any press in a 300 ms window lands the hit. Raise the ceiling: a press inside the middle 30 ms does three times the damage. Newcomers should never know that second number exists.”
Where you’ve seen it
In Rocket League, anyone can drive into a ball and feel useful within minutes. At the top, players fly through the air on boost and steer the ball with their car, using the same few controls.
Not to be confused with difficulty
Difficulty is how hard a given moment is. Floor and ceiling are the range of skill that the game can tell apart.