In order to unlock the song for Call of the Dead, you need to find and activate three meteorites. The first one is in the starting area, forward a little and off to the left on a canister near where you start. The second one you need to get 750 points, and open the path right of the starting area (facing the lake). Go upstairs, ignore the next blockade. Go around the side into a room with some tables. On the far side is a meteorite lying on the seat. For the last one, run back to the starting area and get 750 points for the left path, follow the path to the lighthouse. When you get there, take a right and go down stairs, then go in a room, and go to where the light is at the end of the room. It will be lying on the floor. There will be a pause and then I'm Not Ready to Die by Avenged Sevenfold will play.