To all you people who are complaining about paying: Why don't YOU work on a game for 3 years for absolutely NO MONEY until you finally finish it. THAT'S A LOT OF MAN HOURS, EVEN IF THEY ONLY WORKED 1 HOUR A DAY.
Build 5 military bases then 5 labs immediately.
Only build the giant builders as the Japan AI is easy to beat with ninjas (they never get samurai)
Mass samurai, giants, and snipers
Build a wall around the places where the unidentified can come through.
Use the healing power, don't wait for people to die because Zeus only revives 60% of your troops.