This game is really fun! it could use a bit of balancing when it comes to the spells but then again I like the OP feeling you get when you kill yourself with your own spell :P
Keys To Beating Aliens
1.AT LEAST 5 giants, and a armada of snipers
2. backups: always have a backup army to defend your territory, try to follow the 1st step, and you should be fine incase of breach.
3. (Optional) Money : Wait until your enemy has only one countrys worth of land left, than have an army to defend the point that is closest to enemy country. skip as many days as you like until you have the riches you seek, it might come in handy, after all.
(I Found these steps the easiest to winning the game)
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yep :)