The Lost Planet Tower Defense

Go through Wasteland Area, Lava Area, Purple Mountain, and many others, and keep your astronauts on mission in safety. Your job is not to discover new things, but to keep those, who are going for it, in safety, keep that in mind! Exploration squad is about to start extracting these rare gases from unknown lands on planet X48S. Protect them while they are doing their job, since there is a high chance of getting ambushed by aliens. Build defensive towers, and kill all monsters that are crawling to your main base. Have fun.