I’ve played thousands of video games, mostly not exactly scary… I’m trying to think what might’ve been the scariest…
Certainly the one that claims the prize for “most joysticks broken [in violent defensive maneuvers]” would go to Encounter on the Atari 8-bit computers. There these missile/drones/kamikazes that start at a distance and home in on you, getting faster and faster as they get close, making a humming sound whose pitch increases the closer they get to you, and the higher-level ones dodge and try to sneak around behind you to avoid you turning to shoot them, which is the only way to avoid them getting to you… and the only effective way to do that is to move quickly backwards while turning, but the landscape is full of obstacles, and you can’t see backwards as you reverse! ( example )
It also has parts where you need to fly through an asteroid field way too quickly, which gets quite scary too, though maybe even more “stressful” than scary.