It is easy to beat this game! The secret is gunmen! Once getting past each day, buy nothing else than gunmen. They do the job for you.
Playing on high difficulties is more for the fast clickers. Once you get past Day 10 you should have about 20 - 25 gunmen. That's good. They will take down a man for you every 2 - 3 seconds.
Never stop buying them until you get to 100: When you have 100 gunmen you can start to buy the big guns. Hope it helped, enjoy!
