position your rocket copter carefully outside the range of the enemy tower.
when you keep destroying it, after a while the AI will run out of money and quit rebuilding. then mass land paratroopers that will take out the shield generator and all enemy buildings. you can use your chopper again for help, just dont let it get destroyed. i didnt use a single artillery barrage, just massed paratroopers.
..though I am totally stuck on big ravine...
On first impression, the game looked like a bunch of too many buttons, promising a cluttered and complicated game. I'm glad I stuck. Once i had understood the concepts and found the market not too tedious, this was actually my best gaming time in a while. great concept, great balance. PLEASE continue with another version. Imho, you could make this epic. yes, needs some graphics, depth, ui cleanup.
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The problem was fixed. Sorry for waiting.