Tower of goo was the proof-of-concept. I believe it was made in a game jam type environment. It was popular enough they made a more fleshed out game out of the

Tower of goo was the proof-of-concept. I believe it was made in a game jam type environment. It was popular enough they made a more fleshed out game out of the concept. "world of goo". tower of goo remains as a minigame in world of goo.