WalkOnWalls

The "Aliens vs Predator" game on the Xbox360/PS3 featured a stealth campaign where you play as a xenomorph that could walk on any surface. Wanting to see this mechanic used in more places I used it to experiment with my own character movement and camera management. 

As I learned from Mirror's Edge having a central visual bound to the camera and in this case using it to orient the player relative to standard "up" helps avoid standard first person motion sickness but also avoids becoming detached from your world orientation as the character and camera change position and rotation based on changing surfaces.