Whole game is a physics simulation that runs on GPU. Everything is made of interacting particles. And everything is destructible.
I like physics in games, so I made a game that has nothing but physics. It looks rather retro, a pixelated 2d graphics. But videocard is loaded full by simulating tens of thousands interacting particles.
It took alot of effort to create a good simulation, that would let me build a world of the simulated matter. Here you can see the gifs depicting how matter looked on each step.