Superflat



Superflat is a World Type, first introduced to Minecraft in Snapshot 12w01a, replacing the normal varied terrain of The Overworld with a thin flat layer of dirt.

The terrain consists of one layer of Bedrock, two layers of Dirt, and one layer of Grass; the surface of the world is completely flat and at height y = 4, with the exception of villages. Since the height limit (128) is unchanged, there is then slightly less than twice as much vertical height available to build above-ground structures as compared to a normal world. Mobs spawn as normal, including slimes; however, due to the lack of any overhangs blocking the sky, there is no “Void Fog” as would ordinarily be caused by being close to the bottom.

Because of there being chests in villages, and villages frequently spawning near the spawn point, it's possible to use superflat as a challenge map. However, the high amount of slimes makes this extremely difficult.

The Nether and The End generate normally; they are not flat. In order to create a Superflat world in SMP, the level-type flag in server.properties must be "FLAT", instead of "DEFAULT".

Future
Jeb is considering adding a Spawn Chest to this World Type if the player wishes to use it for Survival sometime after Minecraft 1.1.

Non-Obtainable Blocks and items
Some blocks can be obtainable in a default world but not in a superflat world. These include: Clay Blocks, Moss Stone, Ice, Sand, Sandstone, Snow, Cracked Stone Bricks, Mossy Stone Bricks, Brick Blocks, Glass, Jack-O-Lanterns, Sandstone Slabs, Brick Slabs, Brick Stairs, Dragon Eggs, End Stone, Cake, Cactus, Pine Leaves, Birch Leaves, Baobab Leaves, Melons, Pumpkins, Pine Wood, Birch Wood, Baobab Wood, TNT, Dispensers, Note Blocks, Pistons, Sticky Pistons, Powered Rails, Detector Rails, Redstone Repeaters, Redstone Torches, Redstone Dust, Blue Wool, Brown Wool, Cyan Wool, Green Wool, Light Blue Wool, Lime Wool, Magenta Wool, Purple Wool, Coal Ore, Diamond Ore, Gold Ore, Iron Ore, Lapis Lazuli Ore, Redstone Ore, Lapis Lazuli Block, Sugar Cane, Pine Saplings, Birch Saplings, Baobab Saplings, Ferns, Lily Pads, and Vines.

Some items can be obtainable in a default world but not in a superflat world. These include: Clay Balls, Coal, Bricks, Glass Bottles, Glistering Melons, Potions, Splash Potions, Sugar, Cookies, Melon Slices, Pumpkin Seeds, Melon Seeds, Ink Sacs, Lime Dye, Cactus Green, Light Blue Dye, Cyan Dye, Lapis Lazuli, Purple Dye, Magenta Dye, Cocoa Beans, Clocks, Compasses, Maps, Snowballs, Saddles, and the 11 Music Disk.

Bugs

 * If the player breaks the Bedrock barrier, the player can see that the Void has the same color of the sky while the player is above y=0, but looks normal (black) when the player is below y=0.
 * There is no consistent spawn point unless the player has slept in a bed; the player may respawn far from the previous spawning location without anything in sight. This may be due to the lack of ground at the usual height of about 64.
 * Slimes are extremely common since the level of the land is so low.
 * The void particles will show everywhere. This is because of the world only being 4 blocks tall.

Trivia

 * Although barren, it is still possible to survive on this World Type. For example, the player has access to cows and chickens for food. Although without wood, the player has no access to Crafting Tables, and therefore nothing requiring a 3 x 3 crafting grid, unless they find an NPC village. The Superflat's extreme lack of resources, however, make crafting tables almost useless.
 * With Generate Structures on, the player also has access to the materials that the NPC villages are constructed. Blacksmith chests sometimes have saplings, which would allow the player to grow trees otherwise unavailable.
 * The Nether is unaffected by the Superflat world type, generating normally if visited from a Superflat Overworld. Visiting the Nether is normally extremely hard, as you would need to get a bucket (possibly from a village chest) and take water from a well and pour it on the lava in the blacksmith shop. then you would need to mine it with diamonds (also from blacksmith chest) and that is the only legit way to make it.
 * While Strongholds can not generate on these worlds, a player may visit The End in SMP by spawning an Ender Dragon, killing the spawned Ender Dragon and travelling through the End Portal created upon its death. Like the Nether, the End is unaffected by the Superflat world type.
 * NPC Villages seem to spawn more frequently on superflat worlds than normal worlds, possibly due to the fact that the villages are the only deviations from the completely flat landscape.