Preheat the oven to 350 degrees F (175 degrees C).

Combine ground beef, crushed crackers, 3/4 cup ketchup, onion, 1/4 cup brown sugar, and eggs until well blended. Press into a 9x5-inch loaf pan; lay bacon over top.

Bake in the preheated oven until cooked through, about 1 hour. While loaf bakes, whisk remaining 1 cup ketchup, remaining 1/2 cup brown sugar, vinegar, mustard, and salt together in a bowl; spread over top of meatloaf during last 15 minutes of baking.