Basis of old FPS design, that is why games where so loved back then. The forward design philosophy is one of the causes of FPS fatigue, but people won't acknowledge that.It was one of my favourite aspects in Halo: CE. Many people critisize it for the backtracking and reused levels. I actually loved that. You roam around the levels not knowing wtf is up, find out wtf is up, then you have to go back but not with much more tension because you know wtf is up.