Spirit was an idea our team had where the player could hook onto any surface making that surface the new "ground." This would allow the player to walk on walls and ceilings. Pretty much, there is no up, down, left, or right. We then evolved that idea with a spirit theme to wrap it up. The player would gain these spirit themed abilities to help traverse the terrain and solve puzzles in a 3D environment. There would be the Spirit Hook to hook onto the walls and rotate the environment, spirit grasp to move blocks around from range, spirit sight to see invisible terrain, spirit dash to pass through some terrain, spirit summon to construct your own movable blocks, and a few other concepts.
Overall, the idea didn't seem to stick at all. It would require a lot of tech, a lot of content, and the idea may not be as fun as we thought it would be. Still, I created an animation in 3DS Max to demonstrate this proof of concept. It may not be pretty, but it gets the point across of what the game would kind of be like.