complex and seemingly unbeatable.
i tried playing this game in many different ways many times before giving up.
Ive seen quite a few tower defence games try this style. many of them fail in my book because they are just too difficult and overall not much fun to play.
however i will give you props. you made it original with the whole planet thing.
but its just ridiculous. if its not one thing, its another. something is always needed to be built right after you build something. its annoying.
its hard enough to get money as it is to afford turrets, but when you send 2 giant boss spaceships that my double lasers barely put a dent in and they just fly right on in and take out like 4000 pop, instantly and killing me, well that pisses me off.
its a good game idea, try to tone down the enemy a bit, or reduce costs of everything.