Round 6

"First green bloons are coming next round."

- BTD5 Pre-Round Comment

Round 6 is a round appearing since Bloons TD 4. It serves as the standard first appearance of the Green Bloon. In Bloons TD 6, Round 6 is the first round on Impoppable and C.H.I.M.P.S.

Description
The round starts with four spaced Green Bloons. After a gap, fifteen Red Bloons appear with fifteen spaced Blue Bloons immediately following them.

Strategy
This round is relatively unremarkable outside of Impoppable and CHIMPS, where it is the first round. On CHIMPS, the player starts with only $650 cash on Round 6, and the player gets no aids like Monkey Knowledge or Lives to assist them. This heavily restricts the players' options for starting out that are already capable of defeating Green Bloons. Many Expert Difficulty maps have their Round 6 options even more constricted.

Early-game starts

 * The most typical round 6 start on CHIMPS is three Dart Monkeys. This works on a vast majority of maps, even True Experts, with Spillway, Flooded Valley and Bloody Puddles being major exceptions.
 * Another major start on maps with water is pairing a Dart Monkey with a Monkey Sub.
 * Dart Monkey + Sniper Monkey is a viable option on maps that have minimal or no Line of Sight issues, especially helpful on maps where limited-ranged towers may struggle. Examples of maps that greatly benefit from this starting combo include Geared and X Factor.
 * Quincy is a passable starting hero cheap enough to be placed on round 6. Even some Expert Maps like Muddy Puddles, Sanctuary and Infernal allow a Quincy start.
 * Spillway's unique nature allows for a Ninja Monkey start for CHIMPS on that map. It can be placed on top of the central barrel to hit all the bloons inside.
 * On Flooded Valley, the player must start with a Monkey Sub. There is a specific spot where a single sub will beat Round 6 alone. However, it is also possible to place a second sub mid-round to stay on the safe side.
 * On Bloody Puddles, the player must use a Dart Monkey and a Monkey Sub to beat round 6. The placement of these two towers is essentially pixel-perfect. The Sub must invoke its Moderate Seeking to arc from the middle-right path to the middle-left path, which it cannot directly target; the Dart Monkey assigned to handle the middle-left path is simply unable to do the task alone.

Additional Tips

 * Specific strategies for starting the early-game for CHIMPS can be referenced on BTD6 Starts, a spreadsheet related and managed by BTD6 Index.