Ridiculously hard

Ive been playing since the beginning of not only monkey city but the beginning of bloons TD games as a whole. While I always welcome a nice challenge, this game seems ridiculously hard. Its to the point of absurd. They basically have it rigged for you to spend your gems in large quantities on tracks or attacks that should NEVER be that tough. Im sick of getting to almost the final round then next thing you know there are at least 10 blue MOABS coming at once along with about 2 or 3 of those giant red MOABS and right along with them you have a steady stream of ceramics, regenerating camo rainbows etc. There is no way to prepare for such an attack on these super shortened tracks unless you spend a lot of your gem stones. I dont mind using 5 gems and on some occasions Ill use 10 and even then I get steamrolled into oblivion! Its downright stupid because I know how to strategize and use each towers strength in combination with other towers and theres just no way I should be losing so often & so easily. Put it this way, I have spent the time to upgrade all towers to level 4 which took forever but I have never had enough time on any track so far to even get one of my good towers to its 4th level while in an actual match. Its impossible. Hhhhhhhh so frustrated.

Bigkitties about Bloons Monkey City