Seeing as winning cards is very rare would it be worth introducing different levels of cards say common uncommon and rare and you win more often but you end up with lots of commons etc just so that you actually win something a little more often (thank god f the old trading card games to nic ideas from)
some instructions as to the enemmight be useful cos i don personally know whats missile energy or what, plus how does the population system work? is the pop in empty squares or what?
 "Elements of Arkandia"){kind=icon}
 "Kongai"){kind=icon}
 "PlanetDefender"){kind=icon}