@kamisan It's an option in the map editor to disable movement of the city - but most maps will allow you to move the city.
@wraith1212 just build a line of collectors straight over to the survivor, and don't build any extra collectors unless you can do so without a deficit. (incidentally, this map is actually the easier version of this map - if you have the full version of creeper world you should try playing the original version)
Once you get the healing upgrade and the darkness energy thing from the legendary shop, you can constantly crash into bosses to keep them from being fully on the screen and they stop attacking, and it can be maintained indefinitely.
 "Creeper World: User Space"){kind=icon}
 "Enigmata"){kind=icon}