A guide to the early game and surviving the purple rush on wave 12.
The Early Game
In the early game, the simplest way I’ve found to do defense is to use a dartling gunner. After your first eco injection you should be able to buy a dartling and place it shooting down a straight-away.
Start sending grouped reds and don’t stop until you unlock grouped blues. You’ll want to be upgrading your dartling while you do this (I’m a big fan of 0-2-2, but you can go for 2-2-0 if you feel like it). While you’re upgrading make sure you always have enough money to send constant bloons. Once you see whites, start sending those instead. This isn’t the best way to make eco, but it’s really helpful to have the extra cash while you’re sending so you can place other towers or send bloons on a dime.
Waiting for Purples
While you’re waiting for purples, make sure you buy Hydra Rocket Pods on your dartling and place down any other supportive towers in the mean time. Make sure you keep a money cushion to defend any kind of rush, or send bloons that counter your opponents defense when you notice there’s a bloon type their defense can’t handle. Bide your time.
With your dartling and miscellaneous defenses, you should be able to hold off not just purples, but all bloon types. At this point the only weakness of the dartling gunner is ceramics. Make sure you start sending purples as soon as round 12 hits if you think there’s even a chance that it will overrun their defense. Purples are extremely powerful and if you don’t use them you’re essentially throwing. If you need to, use a monkey or bloon boost.