In 2014 I took a course on VR game development at DePaul taught by Brian Schrank. At the time the Oculus was the only player in the market, and their DK1 headsets were the tool of choice for development. The class focused not just on the minutia of VR game development using Unity, but also how VR game development differs. Brian had previously made a game called Dumpy: Going Elephants that made players wag their faces to wag an elephant's trunk. Brian used the class to try to articulate the idea that the medium of development shapes the final product, and the mechanics should match.
For one of the projects in the class I worked with a few classmates on a game that only utilized the gyroscope for input. I found it funny that wagging your head in VR reminded me of how fish contort their bodies side to side to swim, and from that we prototyped a fish game. Sampson the Space Salmon was a prototype where the player swims through large floating rivers in space by wagging their head to pick up speed. Players can also point their head out of the floating rivers and jump between them.
At the time the game was a test to see how movement would feel in the game given that it's a generally accepted rule in VR game development to not move the without the player controlling said movement. It surprised us to find that the game played reasonably well and we didn't feel motion sick when playing. Granted, it was a small sample size, and because there isn't an "up" in space we had to rotate the player oddly so the planet would be below them, but the final game was an interesting VR experiment for me nonetheless.