Earth Light takes place in a far future where humanity has begun colonizing space. The player commands Earth Federation forces in their fight against the Galt Empire, a collection of space colonies that declared independence from the former. They move squads of mechs along a hex-based grid and fight Galt forces where possible. Fights unfold much like in Advance Wars or Warsong, where both squadrons pit all their available fighters against each other simultaneously hoping to eliminate the other.