According to ESRB, this game contains: Animated Blood & Gore, Animated Violence
Don't even think about playing House of the Dead 2 with a regular controller, because though it does "work," it's pales in comparison to the true light-gun experience. You'll have to purchase either the Mad Catz Dream Blaster or the Interact Starfire Blaster, but expect widely-reported calibration problems with both. We tested only with the Dream Blaster and we were unable to calibrate the gun at a typical shooting distance. We had to bring the gun to a point blank range against the television screen in order for it to calibrate correctly. But it did perform fine after that solution and we didn't have any other technical difficulties. As for the actual game, it delivers more or less what you would expect without surprises. Time Crisis and Point Blank remain a bit more innovative in the gameplay department, but then again, Dreamcast owners have little choice.