Mapping, or called making new custom levels, is a type of the action of modifying levels. However, what makes custom maps (custom levels) entirely different from ordinary modified levels is, custom maps do not, or almost do not, can contain any no parts derived from default levels.

[[File:MonengSpace.jpg|thumb|300px|right|A screen shot of [[魔脓空间站|''Moneng Space''SkyScraper]], the most representative custom level]]