Compulsion loop
Also said as Core reward loop, Engagement loop
A repeating cycle in which an action earns a reward, and the reward makes the next action possible or more appealing: fight, loot, upgrade, fight something harder.
It is how many games stay interesting between big moments, and nearly every action RPG has one. The word is industry slang and the psychology behind "compulsion" is loose. Use it to ask a real question: when does this loop let the player stop?
Say it
“Cap the loop with a natural end: after three missions, the camp scene plays and saving is suggested. People should be able to finish a session feeling done.”
Where you’ve seen it
Destiny is a well-known example, with missions dropping gear that makes you able to take on harder missions that drop better gear.
Not to be confused with core loop
A core loop is what you repeat in a game, and it can be purely enjoyable. People say compulsion loop when the pull is about the reward more than the activity.