State IO (State.io - Conquer the World) is a world-domination game that simulates real-time strategic military planning during nation-building campaigns. The player attempts to conquer red, green and other occupied states with their blue troops to take over regions in a real-world country.
Every region contains two occupied states. If desired, the player can use the shop to switch their color to red and make the opposing army blue. Between the states are inactive gray areas that neither side controls. The player initially receives 10 units of soldiers in their first state. Each state generates one new unit per second.
The player must take nearby inactive states to grow their army's numbers. As long as they attack a state with one more unit than the displayed number, they win the state and generate more troops. After they have enough units from their combined territories, they can direct all their fighters toward an enemy state to overwhelm it. They only need to conquer occupied enemy states to win an entire region.
State IO rewards the player with money after regional and country achievements. The player can increase the amount by watching an advertisement. They use this cash to level up the number and speed of units generated per second. They also use it to level up the amount of money they earn when not playing.