Are there total of 27 story quests? Done them all, but unsure if they were all. Melee units are no longer required, just get your ranged skills really high, and the game should be easy. Not sure if this was done on purpose, it was fun, but I think it's a bit unbalanced.
 "Kamikaze Pigs"){kind=icon}
 "Enigmata: Stellar War"){kind=icon}
 "Protector IV"){kind=icon}