Rocket Storm

"Rocket Storm ability: Sends a powerful storm of rockets in a wide cone."

- In-game description

 is the fourth upgrade of Path 2 for the Dartling Gunner in Bloons TD 6. Activating the ability produces waves of purple missiles for 8 seconds, producing waves (17 by default) of 9 missiles in a wide area that deal 5 damage each to up to 8 bloons, split among 0.467s each wave. Ability missiles are spawned out at a 130° maximum spread (52° with 1-4-0), move erratically, but do not travel past obstacles. Cooldown for the ability is 40 seconds. In addition, the upgrade improves the main rocket attack by giving +2 pierce to both the rockets and explosions, totalling 8 pierce for both. As the rocket itself uses up 2 pierce per bloon, the number of explosions per main rocket increases from 3 to 4.

When crosspathed with Focused Firing, the ability missile spread is reduced by 60%. Crosspathing with Powerful Darts increases ability rocket pierce by +2.

It costs $4,335 on Easy, $5,100 on Medium, $5,510 on Hard, and $6,120 on Impoppable.

Summary
In general, Rocket Storm is a decent midgame upgrade due to the ability providing a burst of power. As the ability is affected by buffs and the main attack also benefits greatly from additional buffs, it is extremely useful to add Stronger Stimulant, Jungle Drums and Pat Fusty/Gwendolin buffs onto the Rocket Storm. It can be used in many situations, including as damage or cleanup depending on the situation. As cooldown is fairly fast, the Rocket Storm can be used multiple times on most rounds.

Note that the Gorgon Storm Monkey Knowledge applies stunning to the Rocket Storm ability, which could potentially be viable in stall meta strategies.

Tips

 * The ability can benefit from crosspathing. Adding Focused Firing decreases the ability missile spread, although the ability missiles are still fairly random. Adding Powerful Darts increases pierce of each ability rocket by +2.
 * 1-4-0 crosspath offers better single-target and single-area damage by focusing its ability rockets at bloons more accurately. However, the ability rockets do not inflict Laser Shock effect with the 2-4-0 crosspath. The 0-4-2 crosspath is more effective at increasing the pierce of each ability rocket, making it a better choice if the screen is crowded full of bloons.
 * The better Rocket Storm crosspath depends mostly on the damage role of the Hydra Rocket Pods attack. Since the Rocket Storm's main rocket attacks gain extra pierce and one more explosion, the main attack is simply an improved version of Hydra Rocket Pods at straightline explosive damage. The 2-4-0 crosspath is more accurate and consistent, while the 0-4-2 crosspath lacks extra accuracy but has overall greater damage potential due to the bonus pierce and extra explosion for the main attack. The trend should be fairly similar for the ability.
 * Rocket Storm ability can stun bloons including MOAB-class if "Gorgon Storm" MK is bought and active. Stunned bloons become stunned for ~0.5s per hit.
 * Like Turbo Charge, further increasing attack speed of the Rocket Storm allows more than 19 waves of 9 rockets to be released for the duration of the ability. For instance, with Overclock it can send up to a total of 32 waves of 9 rockets for the 9-second duration instead.
 * The Rocket Storm ability will be the most effective when large groups of regular bloons appear. Be sure to point the Rocket Storm Dartling in the desired direction while its ability is activated.
 * The rockets from the ability have roughly ~20 blast radius each. This is especially noticeable when paired with the "Gorgon Storm" MK.

Sounds
When activating Rocket Storm Ability:
 * [Rockets firing]

Trivia

 * It can be compared to the BTD5 Bloon Area Denial System, which granted additional projectiles and the ability when upgraded from Hydra Rocket Pods. The BTD6 Rocket Storm adds pierce and ability instead when upgraded from the same previous upgrade.
 * In BTD6, the new Bloon Area Denial System is now an entirely different upgrade, only somewhat implementing the concept of additional projectiles from the BTD5 Bloon Area Denial System.
 * The Dartling Gunner appears more robotic, akin to Tech Terror. It has a similar mouth piece and glowing eyes but an angrier appearance.
 * The helmet and mask of the Rocket Storm becomes more detailed. The mask worn by Rocket Storm bears some resemblance to Darth Vader from Star Wars.
 * The Gunner's Rocket storm outfit looks similar to Vile in Megaman X.
 * Since Arctic Wind got a price buff in Version 23.0, making Snowstorm more expensive than Arctic Wind, Rocket Storm is the only Tier 4 ability upgrade that is cheaper than its preceding Tier 3 upgrade.
 * There was a bug with Rocket Storm during Version 22.0: if Rocket Storm was crosspathed with Faster Swivel, the ability was unable to change direction while firing. This did not affect M.A.D. This was fixed in Version 22.1.
 * Missiles from the Rocket Storm's main attack and ability are all 2D projectiles. On the other hand, M.A.D's missiles are all 3D.
 * Like Bloon Area Denial System, the artwork of this upgrade resembles 0-4-1 Dartling instead of 0-4-0 as the Dartling in the artwork contains a tripod.
 * Rocket Storm is the first non-hero tower to intentionally gain an ability cooldown increase. The Absolute Zero ability initial cooldown increase in Version 23.0 doesn't count because itself didn't get an ability cooldown increase but was indirectly nerfed by not being affected by the Version 23.0 Snowstorm buff.
 * The sound for the Rocket Storm ability is identical to that from Captain Churchill's MOAB Barrage ability when the Hero Voicelines option is disabled.
 * In fact, the internal name for that sound effect is "ActivatedMoabBarrageNoVO.ogg".