Stuck trying to complete a hard level? I know how to help. First, start with a ninja monkey. upgrade it to 2/2, then place a glue gunner and upgrade it to 2/1. Now buy a monkey ace and upgrade it to 3/2. The monkey village is what you need next. Upgrade it to 2/2. Lastly, you get a super monkey and upgraded to 2/4. After that, sell the ninja monkey and nock yourself out. NOTE: This strategy doesn't work with maps that have 2 or more pathways.
I feel that this game should really require a speed up button. I jut get so mad when I put my defenses at the very end and for the next three waves are slow.