In the game, the player builds a city by marking land as commercial, industrial or residential zones. Those zones depend on each other to grow. The player is also required to supply the city with power and connect the different zones by building roads.
OpenCity is the product of programmer Duong-Khang Nguyen and 3D artist Frédéric Rodrigo, along with contributions such as translation and quality testing. Nguyen was inspired by the open source game FreeReign; when he realized that the FreeReign project was abandoned and the code was not in the condition to be improved, he began development on his own city-building simulator.