Either I missed a key, or there aren't enough. If it's the former, there needs to be some way of tracking pickups, because I really don't want to have to go back through the entire damn house looking for it. If the latter, I need to be informed so I don't go back through the entire damn house looking for it.
For anyone wondering, you score points for killing things, but the amount you score reduces over time. So to get three stars, do as much damage as early as you can.