Spoiler warning: Plot and/or ending details follow.
The World of Goo, with the six islands visible, though only two are colored
The video game World of Goo, developed by 2D Boy, takes place on a planet presumed to be the World of Goo that the game takes its name from. This planet is fully seen on the main Map Screen.
Geography
The planet appears to be basically a black sea, with six large islands on it. These islands are all grouped in variance - ranging from grassy hills to a windy desert to an iced-over factory to a station for observing. The planet seems to have very little wilderness, and all the islands contain machinery in some form. For example, gears and blades are a common motif in levels and on the maps. A network of pipes criss-cross the islands, which collect Goo Balls and transport them to the World of Goo Corporation campus, on the northernmost island. The planet has a form of Internet, the Information Superhighway, but it was abandoned years ago. The World of Goo is orbited by a Moon, though this may be artificial.
Several species of goo: Green Goo, Spike Goo, Small Beauty Goo, Black Goo
Life
The World of Goo planet has many life forms, such as frogs, time bugs, and more. The most prevalent life forms on this planet are the Goo Balls, living ball-like creatures made of a jelly-like substance which can attach to each other to form structures. These Goos can enter pipes, which transport them to World of Goo Corporation to build towers - getting Goos to the pipes is the main objective of the game. The reason for these towers is not revealed until the Epilogue. The Corporation, a parody of large consumer companies, is large enough to take up an entire island, and their factory, used for outsource work, takes up another island on the opposite side of the world. They may also have created the Regurgitation Pumping Station, the windmills and the Beauty Generator among other things, but World of Goo Corporation and their factory appear to have existed after the creation of the Information Superhighway and are independent from MOM, despite their similarities.