31 days. I agree that the difficulty should ramp up. It's ridiculously easy to beat the regular provinces. and then it gets significantly harder (although still pretty easy), relative to the normal enemies.
I am constantly shocked at the horrible grammar and spelling in some of these games. It such a simple thing to check/correct. Even if you think it is perfect, just run it by someone. For all the time that must get put into making a game, spend a half hour getting someone to read your text.
I really like this game, but you could make missle launchers a bit less dumb. I had two launchers against three mother ships. The launchers always seemed to target the healthiest ship instead of finishing off ones that were weaker. So I had three motherships lasering me for the longest possible time.