World of Goo is bubbling with ideas. Born from a student project to create a game in just seven days, the original’s single mechanic was the ability to pick up little black goo-balls and place them near one another to form wobbling structures of squishy struts. No goal, no purpose; just a limit to how high you could scroll and the compulsive desire to reach that limit.

From that core idea World of Goo has become much more. In the first chapter you build through rolling hills and out of the mouths of frogs. The second chapter features levels based on beauty pageantry, fame and renewable energy sources. Primarily the work of just two people, Kyle Gabler and Ron Carmel, WoG feels like they’ve mapped the inside of their brains onto a videogame. Whatever they were thinking about at the time, whatever they care about, it’s all grist for the mill.

At its core, WoG is still a physics-based puzzle game; a game about structural engineering. Each level gives you a limited number of goos, a required number you have to save and an exit – a sucking pipe – to build towards. Completing a level means using the goos to build a structure toward that pipe, while having enough unused goos left over to climb up the structure to safety. Across four chapters and an epilogue the game introduces new obstacles and new types of goos. You’re constantly battling gravity by trying to build a structure that can support its own weight, but you’re also building around, under and over spinning blades or spiked walls or flaming pits. You begin with simple black goos that are locked in place once used, but soon you’re using green goos that can be repeatedly picked up and re-positioned, balloon goos that float upwards, giant, grinning beauty goos that can be smashed apart, and more.