The game features a number of cities where subway lines are laid out and optimized. The interface makes altering existing lines difficult; right-click line removal and station color outlines would assist in making designs more efficient. Lines are constructed simply by dragging between stations, which appear over time on the stylized map. Additional trains, bridges, tunnels, and other upgrades increase transit system performance, and the free-form solutions are welcome. Mini Metro has novel but repetitive gameplay with a poor interface.