Games like Earth Defense Force 4.1: Mission Pack 1 - Time of the Mutants

If you finished Earth Defense Force 4.1: Mission Pack 1 - Time of the Mutants, the closest matches are Ranger X, Half-Life: Uplink, Neptunia Shooter, Ghost in the Shell: Stand Alone Complex - First Assault Online and Mech Arena: Robot Showdown. All 6 share its shooter genre and are ranked by how closely their themes and modes overlap.