completionist

[ kuh m-plee-shuh-nist ]
/ kəmˈpli ʃə nɪst /

noun

(in a video game) a player who attempts to complete every challenge and earn every achievement or trophy: I’m not really a completionist, so I skipped the side missions and focused on the main story quests.
completist(def 1).

Origin of completionist

First recorded in 1970–75; completion + -ist

Words nearby completionist

completely normal space, completely regular space, completer set, completing the square, completion, completionist, completist, complex, complex absence, complex analysis, complex carbohydrate