'Unending' is a powerful word, I dunno if I can think of one, but the one that would come closest is Fallout 3 or Bioshock maybe.
Unless it doesn't have to be a video game, then it's the zombie game I invented when I'm walking around by myself in a crowded public area. You pretend everyone else is a zombie and you need to find the best route through them all without bumping into someone. You also have a "revolver" with six rounds and every time you need to say "Excuse me" to get past someone it counts as a shot. Also, if someone needs to excuse themselves to get around you, you just got eat, bro.