hint: make it in on one side.
l----------------------------l
l t get it (i think almost all.)
go to http://www.youtube.com/watch?v=ulziz3oq_l4&annotation_id=annotation_552731&feature=iv ctrl+c
challenge 5 tips
first unable the coal plant disable,make metal mine,
make oil well,make natural gas power plant,make lab, make flameturret around the oil well and the power plant,and the metal mine,and around the fortress.
wait and keep upgrading natural gas power plant.and don't forget to upgrade the natural gas for the garbage truck and wait.................................. and if you want +score make almost 3~5 truck,
make nuclear plant and 1engineer
and the lab thing to upgrade nuclear plant
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