User blog comment:AugFC/MW3 - Review/@comment-92.84.105.123-20111231161301/@comment-3967954-20111231210415

Most FPSes are linear and lacking in freedom. STALKER is the only FPS that has a really open world that I can think of, but it's sort of a hybrid traditional FPS / Free-roamer: It has "levels", but the player can finish these levels in any way they wish.