Board Thread:Questions and Answers/@comment-202.150.1.24-20130417103156/@comment-8238000-20131202205727

Just use some Appretices. The 1st path upgrades 3 and 4 suck, but 2nd path is amazingly powerful. Try with 2/2 if you are short of cash, or 2/3 for Maximum Efficiency, although is not recommended for other bloons types, I reccomend Dartlings, Super Monkeys. Use your own strategies, mixed with these. Easy, huh?