Ground Zero (BTD6)

"Bomb damage increased significantly. Ground Zero Ability: Drops a huge bomb that destroys most things on screen."

- BTD6 Upgrade Description

Ground Zero, is the 4th upgrade on Path 2 for the Monkey Ace in Bloons TD 6. It adds a new ability that drops a nuke, which deals 700 damage onto up to 1000 bloons nearest the center of the Ace's runway upon detonation. Compared to its BTD5 counterpart, it deals twice the damage but requires a 0.8s deployment cooldown and no longer has infinite pierce, albeit arbitrarily high pierce. The nuclear explosion affects the whole screen, starting with the bloons closest to the Ace's runway, and can penetrate blimp layers. The ability has a cooldown of 45 seconds.

In addition to an added ability, the Ground Zero plane now drops improved Bomber Ace bomb arrays that deal 10 damage per bomb instead of 3, and bombs pop 40 bloons instead of 20 (52 instead of 32 with 0-4-1). The bomb arrays still cannot pop Black Bloon properties, but the ability bomb does.

It costs $15,300 on Easy, $18,000 on Medium, $19,440 on Hard, and $21,600 on Impoppable.

The Operation: Dart Storm is no longer on the same path as the Ground Zero, and instead that upgrade is a Tier 4 upgrade of its own.

Description
Ground Zero is a green military-style monoplane. Shown in the upgrade artwork is the plane dropping a green-and-black nuclear bomb. Unlike in BTD5, which appeared as black-colored B-2 Spirit Bomber, the Ground Zero plane resembles a A-26 Invader instead, to appear in line with the airborne explosives upgrade theme.

As the new description of Ground Zero reads, the bomb arrays now deal significantly higher damage compared to Bomber Ace's bomb arrays, 10 damage instead of 3, although these same bombs still cannot affect bloons with Black Bloon properties (unless with Monkey Intelligence Bureau or Striker Jones Level 5+).

The Ground Zero upgrade also comes with an ability that deals 700 damage to up to 1000 bloons on screen, prioritizing the bloons closest to the explosion radius. One use of this ability is enough to eliminate non-fortified MOABs and non-fortified DDTs before Round 101. Just like in BTD5, Super Monkey Storm can be used instead, but it costs much more Monkey Money to purchase Super Monkey Storms than in BTD5, and Ground Zero can penetrate through MOAB-class bloons. Note that there is an initial cooldown of 15 seconds before initial activation.

Each Ground Zero will have a cooldown of 45 seconds upon activation, along with approximately 0.8s seconds before the special Ground Zero bomb explodes on impact.

The landing base will have green borders upon purchasing the upgrade.

Costs

 * Updated as of Version 30.0

Summary
The Ground Zero upgrade is substantially stronger in BTD6 compared to in BTD5, not only packing with a powerful nuke ability but also much stronger bombs. These arrays of bombs deal a massive 10 damage each, significantly stronger than its dart attacks. When micromanaged carefully by ensuring the bombs explode when the bloons do not turn into Blacks or Zebras, Ground Zero is unformidably powerful on its own, and even comes with an emergency ability that is able to deal 700 damage to an extremely high number of bloons on screen, enough to wipe out virtually all bloons, MOABs, and DDTs on screen. Because of its powerful versatility, a single 1-4-0 Ground Zero has been used to successfully complete multiple 2TC challenges and LCC (Lowest Cost CHIMPS) challenges.

Tips

 * When it comes to optimal crosspathing, this upgrade benefits the most from the Rapid Fire crosspath, as this upgrade will allow the Ground Zero to produce arrays of bombs much faster, from every 1.36s to every 1.02s. Sharper Darts increases pierce of bombs by +12, but Ground Zero bombs have great pierce already. Lots More Darts is nearly useless, but Centered Path grants access to a new style of Ground Zero micro plus central access.
 * The Ground Zero bomb arrays deal massive damage compared to Bomber Ace. As such, it is an excellent option for beating mid-game, but does require a decent amount of supporting towers due to the general unreliability of each of the bomb arrays.
 * Make sure to watch out for the 0.8s time delay before the Ground Zero nuke explodes after activating the ability. Prepare the ability before the bloons reach the exit.
 * Several Ground Zeroes can be used to beat rounds with regular DDTs easily. Two or three of these abilities with a slight delay between each Ground Zero ability usage may be required to beat Round 95. Two simultaneous Ground Zero abilities may be required to beat Round 99's Fortified DDTs.
 * The limited 1000 pierce of the Ground Zero ability shouldn't matter in any situation except where there are severe Regrow Farms or on Race Events.
 * Ground Zero has high synergy with the heroes Admiral Brickell and Psi. For Brickell, it is chaining Mega Mine with Ground Zero ability to wipe out high-HP blimps. For Psi, it is to make mid-game more manageable and deal with weaker blimps without reliance on Psionic Scream.

Sounds
When activating Ground Zero Ability:


 * [Explosion]

Trivia

 * A common abbreviation for Ground Zero is "G0" or "GZ".
 * The Ground Zero ability in BTD6 currently does twice as much damage as the current damage that BTD5's Ground Zero ability currently does (700 over 350).
 * It however no longer has infinite pierce like its BTD5 counterpart but still has extremely high pierce nonetheless.
 * The Bomber Aircraft is roughly based on the "A-26A Invader".
 * Ground Zero was not affected by pierce nerfs to Exploding Pineapple bombs or Bomber Ace bomb arrays, but the pierce buff interaction with Sharper Darts affects Ground Zero.
 * Instead of producing regular 16-dart volleys and explosive pineapples, like the BTD5 Ground Zero, BTD6 Ground Zero produces high-damage bomb salvos.