I think the reason no one has a walkthrough for the hard badge is cuz almost everyone just loads the cheat. I've looked at half of the comments and people say...start with a few monkeys then a few bombs. You cannot raise enough money to buy one bomb before it gets too much for your two lonely monkeys to handle. I did find two helpful hints I'm going to try next..but so far i'm on attempt #12 with no luck. I refuse to be a cheater!!!!!! lol
 "Parachute Retrospect"){kind=icon}
 "Chronotron"){kind=icon}
 "Bloons Tower Defense 2"){kind=icon}
 "Kongai Launch"){kind=icon}