As per the developer, you need to complete the following list of maps. You must get at least 95%, of course.
* Athena's Wrath
* Waste Disposal
* Paintenance Tunnels
* Frostbite
* Unrefinery
* Caduceus
* Overgrowth
* Incubation Emergency
* Gravity Drive
* Hydroponic Hell
* Revolutionary Robotics
* Unearthly Excavation
* Cryogenesis
* Evil Science