De85 on 23 September 2008
One run through of the main story is about 6 hours, at 3 days and 2 hours per day in-game. The Overtime mode adds 1-day/2 hours, which is still rather short, but a lot of the appeal of Dead Rising, at least on 360, was the added replay value due to the achievements.
Getting the Saint achievement your first playthrough is all but impossible. Zombie Genocider requires another playthrough all its own, plus there's the infinite mode where your only objective is find food and stay alive. If you do all there is to do you can easily sink ~50 hours into it, at least on 360.
