World of Goo is a puzzle game where you use balls of goo to create bridges that span increasingly large chasms and obstacles. The game simulates real-world physics to determine if structures are strong enough and when they collapse. This means that solutions often stretch the materials to breaking point and invite ambitious strategies.

You play through five chapters that offer levels with unique graphical and musical themes. Your objective is to get the required number of goo balls to the exit. To do this you need to use some of the balls to construct bridges, towers, and other structures. In your way are chasms, hills, spikes, windmills and cliffs.

As you progress you gain different types of goo balls, each with unique properties. These need to be used to complete each level. You are awarded points for how many goo balls you get to the exit (and by implication how efficient your structures are).

There's also a Portal-like subplot about a sign painter watching you and the World of Goo Corporation that isn't all it seems to be!