Preheat an oven to 375 degrees F (190 degrees C). Mix the ground beef, sausage, mushrooms, onion, barbecue sauce, Worcestershire sauce, egg, oatmeal, garlic powder, pepper, and Cheddar cheese together in a large bowl until evenly mixed. Form into a loaf and place in a 9x13-inch baking dish. Lie the bacon strips across the top of the meatloaf. Bake in the preheated oven until no longer pink in the center, about 1 hour. An instant-read thermometer inserted into the center should read at least 160 degrees F (70 degrees C).