Quad/Strategies

This is a page containing strategies for the Expert Map Quad from BTD6.

The Killzones
Many Quad strategies rely on setting up two killzones, marked in red in the following image. One killzone (the bottom-left section of track) collects all bloons coming in from the bottom and right entrances, and the other killzone (the top-right section of track) does the same to the top and left entrances. By design, these killzones allow some time for the rest of the defense to chip away at bloons coming from the top and bottom entrances before the bloons from the left and right entrances double up on the defense. If the killzones are overrun, the result is generally lethal unless the player has a panic button ability ready to go. The killzones also have the advantage of easier diagnosis of leaks, which comes in handy as Quad is notorious for allowing leaks to blend in with recently spawned bloons with deadly ease.

The killzones themselves are almost always staffed by Spiked Balls boosted with Berserker Brew, allowing for the effective popping of both Super Ceramic Bloons and, with DPS and support assistance, early MOABs and later DDTs. To prevent overcrowding of the killzones by late-game ZOMG and BFB rushes, a combination of MOAB Glue, MOAB Press, and Bloon Sabotage is recommended. In the early game and Half Cash, a Wall of Fire in one killzone (or both, if needed) remains cost-effective early popping power. In Half Cash, low-level Ice Monkeys in front of the Walls of Fire give them much more room to breathe and even allow them to be viable until Round 75.

Beware of Round 94, as it will force only two ZOMGs into the top-side killzone but four ZOMGs into the bottom one.

Tips

 * The sole viable CHIMPS start is three Dart Monkeys, two of them placed in the quadrilateral's side corners, and the third placed on either the top corner or bottom corner. On Round 7, either the right Dart Monkey (if using the top corner first) or the left Dart Monkey (if using the bottom corner first) must be switched onto Strong.
 * Monkey Subs do poorly on this map in mid-late game as while they can cover all of the tracks with Advanced Intel, they will always be shooting perpendicularly to the track, making the subs not use their airburst dart pierce to their maximum. However, Airburst Darts is a viable early game option, being able to handle difficult early rounds such as 15, 22, 27, 35, and 36 (if Triple Guns is bought with alchemist buff).
 * A Grandmaster Ninja is able to reach all four paths if placed correctly with the Arctic Wind to freeze the water.
 * MOAB Maulers combo very nicely with Spiked Balls, and for a long time has been a favorite Black Border strategy. The spammable nature of Maulers and Spiked Balls makes the DPS throughout the game significant while not having to make any difficult save-ups, such as other strategies would have to make to get a key tier 5 tower, like a Grandmaster Ninja, Prince of Darkness, or Sky Shredder.
 * First Strike Capability comboed with a nearby Reactor has enough cooldown time to have two uses of the ability while attempting to kill a Round 100 BAD. It works for Quad CHIMPS runs against Round 100 if the left and right trusses are removed.