You are surrounded by 100 spheres, 15 of which are awake. Awakened spheres are bad. They stay still while you're watching, but zip away when you're not looking. Your goal is to find these 15 spheres and click on them. Unfortunately, clicking on a sleeping aphere naturally wakes it up. Good luck!
My goal when starting was to make a game where the inhabitants of the virtual world were effected by where the player is looking.
After considering several iterations of more complicated ideas involving mazes and flying/running things, I arrived at this simple model which demonstrates the basic idea of objects which behave differently when they are being observed. In implementing the game, I decided to take it one step further and actually use a rendering of the visible polygons from the observer's perspective to drive game mechanics. This method is unfortunately slow, but also easily allows for some objects obscuring others.
I suspect few games literally consider what's rendered to the screen. While many games will have objects which react to the player's presence, few can likely react to exactly what the player can see.
My game achieves my goals, but I also believe it provides the least interesting gameplay of my games so far. Something more needs to be happening with the objects onscreen and the player needs to be able to do more than just rotate in place.