In Burger Stack, you have to stack up as many 20-layer burgers as you can. Drop the lettuce leaves, omelets, bacon strips, meat patties, cheese slices, and onion rings onto the center of the burger bun. Try not to veer too far off-center or your burger will become crooked and wobbly. The neater your stack the more stable your burger will be, but if your burger becomes lopsided the wobble will be difficult to recover from. The 20th layer is always the top of the burger bun, and if you've completed a burger you can start on the next one. How many burgers can you stack?