Defunct is an adventure game where you race through a post-human landscape. You play an old, broken racing robot with little propulsion left. However, by using the landscape and varying your gravitation pull you learn how to speed through the world. It's an unusual way to get around that leads to a sense of achievement and flow reminiscent of skateboarding or skiing.

Play involves using this gravity-altering technique to explore the environment. Turning up gravity when going downhill increase your speed and turning it off when going uphill will result in less of a decrease in speed. You can also collect speed boosts throughout the levels. These offer orb-shaped speed bursts or bottle-shaped boosts that can be used when you need them. You can also magnetize structures you find so you can stick to surfaces and grind along them when going upside down or vertically.

In this way, you race through the world, meet robots, fly through junkyards and boost your way back to your ship. There are 11 varied spaces to explore each with unique climates, biomes and challenges.