InnerSpace is part adventure game, part arcade flight simulator. In this game, you play as a newly sentient airplane/submarine hybrid exploring the world of the Inverse. You fly around a handful of self-contained maps searching for relics and collecting Wind to unlock new plane models.
You do have one special trick up your sleeve when it comes to flying, and that is the drift ability. By simply holding a button, you can turn your plane in any direction while still maintaining your momentum. You can turn corners you wouldn't otherwise be able to without the drift, and can even turn a complete 180 degrees on a dime.
There are a handful of different maps for you to explore in InnerSpace. Each one boasts slight variations on the same minimalist art style. Each level itself is open for you to explore and filled with a few secret areas, sometimes containing relics for you to collect.
Relics allow you to unlock new airframes, each with its own benefits and drawback. For example, one airframe allows you to zoom through the air in straight lines faster than any other plane model. However, drifting with this frame stops you almost dead in your tracks. Another airframe, while not as fast on the straightaways, is much more nimble and can drift around nearly any obstacle. There are about five different plane models to unlock.
The story of InnerSpace has you trying to collect as much information on the Inverse as you can so that you can take that information back and share it with others. Along the way, you have the chance to encounter and speak with demigods, who explain to you how the world of the Inverse came to an end, the importance of Wind, and how the society of the Ancients came to an end.