zeroranger took me more than 6 hours because i suck. this can technically be true for a lot of the games there but it's especially true for that one.

The Mega Man 2,3,4, and 5 that you used are the gameboy games.

(for clarification, a full playthrough of zeroranger is definitely shorter than 6 hours. but unless you're like some shmup god or something, it's probably going to take you a fair few attempts. you can't credit feed and it's longer than the average shmup. so for most people id call it unrealistic, even if it technically fits here)

zeroranger could fit if not the last boss

Just about every arcade game could fit on this

pretty sure the snes donkey kong country games fit here as well