Ozma Wars is a scrolling shooter conversion of Space Invaders. Instead of discrete lives the game instead has a constantly depleting energy figure. Getting hit drastically reduces the figure, and at zero the game ends. Enemy patterns appear in waves, and after every four waves a mothership will appear that replenishes energy. Enemies come in several varieties with unique abilities, such as tiny enemies that appear in swarms, saucers that shoot bullets and missiles, and space ships that bank and sink into the background in a simulation of 3D space.

Due to the game being monochrome and a conversion kit for Space Invaders, many Ozma Wars monitors used the Space Invaders color overlay.