What is the goal of the game "Bloons TD Ninja Kiwi"?

The goal of “Bloons Tower Defense,” which is Ninja Kiwi game, is to stop bloons from successfully making it to the end of the stage by popping them with tacks, bombs, ice and darts. There are 50 levels in total, and each gets progressively harder.

Gamers play “Bloons Tower Defense” with a computer mouse. The player chooses which popping tower he wants to buy and then selects an area on the map to place it. Popping a bloon earns the player money that he can use to buy more towers or to upgrade the towers that are on the map. He can also sell towers for 80 percent of the money that he paid for them.