World of Goo is a physics based construction/puzzle game. The millions of Goo Balls who live in the beautiful World of Goo don't know that they are in a game, or that they are extremely delicious.
You take control of a bunch of "goo balls" that need to be rescued by creating a network of goo from the starting point to a pipe. You'll need to be extra careful and think twice before you act as your hard-built structures are almost always just a step away from collapsing.
The game is built around the idea of creating large structures using balls of goo. It is based on the prototype game Tower of Goo developed for Kyle Gabler's rapid game prototyping Experimental Gameplay Project. The game is divided into five chapters, each containing several levels. Each level has its own graphic and musical theme, giving it unique atmosphere. There is also a bonus meta-game called World of Goo Corporation, where the objective is to build the highest tower using goo balls which the player collected through the course of the game. Players from all over the world can compete, as the height of the tower and number of goo balls used are being constantly uploaded to the 2D Boy server.
The main objective of the game is to get a requisite number of goo balls to the pipe representing the exit. In order to do so, the player must use their various abilities to build bridges, towers and other structures to overcome gravity and various terrain difficulties such as chasms, hills, spikes or cliffs. Extra Goos recovered in the pipe are pumped through to the World of Goo Corporation, a sandbox area where the objective is to compete with other players worldwide by building the tallest tower possible. Players can also try to achieve the "Obsessive Completion Distinction (OCD) Flag" for each level by completing the level under more stringent criteria, such as collecting a larger number of Goo balls, finishing under a set amount of time or using as few moves as possible.
Levels and chapters in the game are interspersed with cut scenes.
There are many types of goo balls in the game and each of them has unique abilities. The player needs to exploit their combinations in order to complete each of the levels.