Runoveryou is a Run Over "simulator", in a way.
You play as a driver who got tired of those who doesn't belong on the road, so he decide to take manners into his hands, or more accurately, his wheels.
Drive your vehicle and run over who ever is in the way, play different game modes, customize the game in the "Mods Garage".
You can also create mods If you have the right technical skills, using Unity3D to build your own characters, vehicle, road, obstacles and sky.
It can be done pretty easily using asset-bundles, please read the manual for more details on how to do that.