There isn't a single title—video game development involves many specialized roles. The term depends on the person's specific responsibilities:
Larger studios often have more granular titles: Gameplay Engineer, Tools Programmer, Combat Designer, Systems Designer, Environment Artist, Character Artist, VFX Artist, UI/UX Designer, Live Operations Manager, etc.
Bottom line: "Game developer" is the safe umbrella term. For precision, use the specific discipline: programmer, artist, designer, producer, etc.