The first start of the hardcore series was come from from this tallest building, The SkyLayer Survival or SLS were made up as a series when time pass. There's two way to play this map! first is to race with friend who will reach the ground first or do it as a team. and the second will be do every achievement in the game and reach at y4 longer than 1 minute...
The SkyLayer Survival map is another good map to challenging yourself and friend. This survival is like a tower of level survival. You can use all of the resource on the map. The whole target of this map is to survival and reach the ground from layer by layer.
Recommended to play for 1-2 players!