In ShortThe family-friendly chain, with its blue and metallic furniture and bright-pink neon lights, has a clear retro spark. The hamburgers range from 5.5 to 20 ounces; completion of the latter will get the customer's picture displayed on the wall next to other "Wall of Famers." Burgers and sandwiches can be crowned with any of the 20 different toppings and a variety of cheeses. The 56 shake flavors include chocolate, watermelon, peanut butter and more.