The Underground World is the fourth level in Craft the World. The difficulty is set to hard in campaign. It consists mostly of earth and stone blocks, along with some sand. The weather type is rain, which provides water and lakes on the surface. A new rock called sulfur can be used to make gunpowder for guns and ammo. The underground is very deep.
World Features[]
Creatures[]
The Underground World features new animals and monsters.
Animals:
Caterpillar (equivalent of the Sheep / Llama)
Cave Beast (equivalent of the Wild Boar / Bull / Ice Boar)
Flying Octopus (equivalent to the Hen / Ice Bird / Blue Bird for drops, but also flies and attacks)
Small Caterpillar (equivalent of the Slug)
Monsters:
Two creatures that spawns in other worlds, do not appear in the Underground World: the Giant Spider and the Giant Worm.
Technologies and Items[]
The Underground World also features completely new technologies, each of them with its items.
| Local Cuisine | |
|---|---|
| Tier | 3 |
| Prereq | Basic Processing |
| Unlocks |  Dried Mushrooms Mushroom Salad Mushroom Soup
|
| Leads to | Advanced Illuminating |
| Chitin Processing | |
|---|---|
| Tier | 5 |
| Prereq | Basic Decorating Advanced Processing |
| Unlocks |  Chitin Helmet Chitin Armor Chitin Boots
|
| Leads to | 
|
| Firearms | |
|---|---|
| Tier | 7 |
| Prereq | Advanced Weaponry |
| Unlocks |  Gun Muzzle Trigger Mechanism Gunpowder Pistol
|
| Leads to | Expert Armor |
| Substance Transformation | |
|---|---|
| Tier | 11 |
| Prereq | Master Alchemy |
| Unlocks |  Mithril Ore Gold Ore Silver Ore Iron Ore
|
| Leads to |
|
| Lead Rain | |
|---|---|
| Tier | 12 |
| Prereq | Master Weaponry |
| Unlocks |  High-Powered Rifle Incendiary Ammo
|
| Leads to |
|
Some items were added to already existing technologies:
Steel Ladder to Expert Construction
Mushroom Pies to Advanced Cooking
Steel Wall to Master Construction (replacing the Brick Wall, which was moved to Advanced Fortifications)
Rifle and 
Steel Ammo to Expert Weaponry