Golden Boxes are boxes that contain special weapons, armor, or special items that improve your health, accuracy, or weapon storage. There is almost one hidden in each map in Zombotron 2 and Zombotron 2: Time Machine. They work like normal chests and disappear after being opened. They can be moved by shooting or by using an explosive.
They also look like secret chests. Most of them are visible and not hidden, while some of them are hidden. For an example, a golden chest that has a minigun inside of it. And it is hidden inside a wall.