Advertisements would certainly be a better idea than what we have right now, but if the developers are set on selling us virtual currency, then there is an alternative. How about a sort of token allowance system. Bronze rank allowance might cost 2$, and give you five tokens every in-game day. 5$ for silver, and that'd net you 10 tokens every in-game day. And then a gold rank would give you 25 token a day. That'd mean you could play the game after a single purchase, but it would leave the door open for people who have played poorly to need to buy more tokens, because they've been wasteful. And the sales from the allowance would be pretty good, I reckon.
I'm not sure, but I think that when you get a discount on levelling up your units, the sparkle effect still doesn't turn up until experience is at the base level. Minor bug, but annoying when you need every upgrade the second you can get it.
It's a decentish game. The dialouge could be less... Suburban. And perhaps there could be other ways to settle things other than blast the hell out of people (bribery?) but overall, I thought it was decent 3.5/5
A good start, smooth it, unbug it, lengthen it, and you'll have a darn good 2nd game.
Oh and by all that I don't mean copy this game, no, make new one. Okay.