itch.io

Is there a campaign map beyond Desolate Rift, Overgrowth, and Nuclear Production Complex? I see other built-in maps in the editor but I don't see them available in the campaign screen to unlock or play. 

You complete a mission by launching your core (usually on an multiple of 10 waves). The resources in your core at that time are launched and can be spent on upgrades. Late in the game, like fellow_human said, you can research a launch pad that can actively launch materials into space while you're still playing the mission. Launched materials can be used for upgrades while you're in the middle of a mission.

You must launch those materials off the planet before you can spend them on upgrades.