The Robobot Armor retains the basic shape of the Invader Armor, but with details that make it resemble Kirby. It has a predominantly pink frame with pale yellow details and red feet, as well as a Kirby-like face on its front. It has a blunt silver spike on each shoulder, resembling the tip of a screwdriver. The Robobot Armor also has a bronze-colored jetpack strapped behind it. When inside of the Robobot Armor, Kirby gains a pair of goggles that rest atop his head.
The color and design of the Robobot Armor changes when it takes on a different Mode. It can also morph the spikes on its shoulders into various tools, such as a Wrench or a Drill.
Stickers, of which there are over 200, may also be collected during gameplay and can be attached to the Robobot Armor's arms to change its appearance. Two different stickers, one on each arm, may be attached to the Robobot Armor at one time. If no stickers are applied, the Robobot Armor's shoulders feature winged gears with yellow stars in their centers by default.
The Robobot Armor is a durable suit that takes a low amount of damage from most enemies. It is also powerful, as in its normal Mode, it is able to lift, punch and destroy heavy objects and enemies that are otherwise impervious to attack. It can also interact with certain devices by transforming its arm into a wrench or screwdriver; Kirby mainly uses this to twist and remove screws, but it can also activate devices such as cranks.
Pressing B near a Copy Ability-bearing enemy allows the Robobot Armor to scan it and take on a Mode based on that enemy's Scan Spec. There are fourteen Modes (including Kirby: Planet Robobot’s final weapon) that the Robobot Armor can take on, each with its own powers and abilities. Copy Abilities and Modes are separate from each other; in other words, if Kirby has a Copy Ability when inside of the Robobot Armor, it does not affect the Mode of the Robobot Armor.
Despite its large size, Robobot Armor is still able to perform a double jump and hover a short distance, dash, ride on a Warp Star and fit in a Cannon. Guarding in Robobot Armor causes the armor to ball up, retracting its arms and legs. However, it cannot truly fly (without the Jet or Parasol Modes), and its large size prevents it from entering certain areas. Robobot Armor will also disappear if Kirby tries to exit a stage while using it.
Areas featuring Robobot Armor tend to feature mechanical stations that allow Kirby to mount and dismount it at will; the station compacts the armor into its spherical form to store it, allowing Kirby to re-enter it later if it is needed again.
The default form of Robobot Armor. It can scan some enemies and gain a Mode based on that enemy's Scan Spec. It is also able to perform a three punch combo attack. It can survive most attacks without receiving damage, which is often used in ways such as jumping on enemies. However, it can only perform a double jump and a short hover before falling.
Allows the Robobot Armor to send out a small bomb robot that can move forward and climb walls. Three of these robots can be sent out at one time. Charging the move sends a bomb robot soaring through the air.
Gives the Robobot Armor two large saw-blade arms that can be thrown through the air in a circular path, upwards and downwards. It can also punch, charge to send a saw-blade flying ahead and spin the saw-blades.
Transforms the Robobot Armor into a small plane, allowing it to fly freely. Its primary weapon is a burst-fire gatling gun, which can be charged to release powerful missiles both ahead and behind it. It can also perform a dodging maneuver.
Transforms the Robobot Armor into a car-like vehicle, allowing it to charge forward and pierce enemies with lance-like spikes projected from beside its front wheel. It can also change planes at will (if other roads are available) and spin in place, causing a fiery blast.
The Robobot Armor has scanned Meta Knight's ship! It's equipped with the Planet Buster. Capture debris, and press A to fire it!”
— In-game description for Halberd Mode • Kirby: Planet Robobot
The final weapon of Kirby: Planet Robobot is the Robobot Armor's Halberd Mode, which is obtained through analyzing Meta Knight's signature warship. It is used during the final boss battle with Star Dream.
The Halberd Mode is able to fire rapid shots from the Combo Cannon and spin in place to deflect some projectiles that come towards it. It also has the ability to absorb debris created by shooting down Star Dream's attacks; when enough debris is absorbed, the Armor can launch a powerful attack known as the Planet Buster.
At the end of the battle, the Robobot Armor's Halberd Mode is damaged by a shot from the Access Ark, prompting Meta Knight to activate a special eject function that fires the Robobot Armor from the front of the Halberd. At this point, the armor reveals its ability to extend a gigantic screw, which it used to pierce Star Dream's barriers and finish off the rogue machine.
Run down evil with boundless energy! The mysterious Zig Zap!”
— In-game description for Beam Mode • Kirby: Planet Robobot
The unstoppable marching bombs! Boomstepper!”
— In-game description for Bomb Mode • Kirby: Planet Robobot
The blade of justice cleaves the sky in two! High-speed Whirling Saw!”
— In-game description for Cutter Mode • Kirby: Planet Robobot
The mind is the ultimate weapon! Psithunder Flash!”
— In-game description for ESP Mode • Kirby: Planet Robobot
Like the tail of a red dragon in burning flame! Burn 'em down with Crimson Tail!”
— In-game description for Fire Mode • Kirby: Planet Robobot
An ice-cold crusher! Evil shivers at the mere sight of... Snowstorm!”
— In-game description for Ice Mode • Kirby: Planet Robobot
There's no escape from these wings. Lock on... Missile Salvo!”
— In-game description for Jet Mode • Kirby: Planet Robobot
Explosive volume keeps their heads ringing. Destructo-Amp!”
— In-game description for Mike Mode • Kirby: Planet Robobot
Twirl, float, and reach for the sky! Become the wind… Parasault!”
— In-game description for Parasol Mode • Kirby: Planet Robobot
A shocking surge of electric power! Watch out for the Cannon Blast!”
— In-game description for Spark Mode • Kirby: Planet Robobot
Release your rage with rocky punches! Earth-shaking Rock Crusher!”
— In-game description for Stone Mode • Kirby: Planet Robobot
Cut evil down to size with the sword of science! Power Beam Saber!”
— In-game description for Sword Mode • Kirby: Planet Robobot
The legendary racer zooms down the track. 3, 2, 1... Turbo Accelerate!”
— In-game description for Wheel Mode • Kirby: Planet Robobot
The Robobot Armor appears in almost every stage in Kirby: Planet Robobot.
The technique used by the Robobot Armor to scan enemies bears a similarity to the Copy ability's Analyze Beam.
ESP is the only Copy Ability introduced in Kirby: Planet Robobot to have a Robobot Armor Mode.
Mike is the only limited-use Copy Ability that has a Robobot Armor Mode.
When Kirby enters the Robobot Armor, his health meter is completely restored.
The Robobot Armor may be an homage to Gurren Lagann, an anime series featuring a drill-themed mecha that adapts the powers of other machines and organisms. The attack Kirby uses to finish off Star Dream looks extremely similar to the "Giga Drill Break", a famous attack used in Gurren Lagann.
Two pieces of concept artwork for Robobot Armor were merged and became the foundation of Susie's Business Suit.
The Robobot Armor is similar to the Ride Armor from the Mega Man X games, as both are mechanical armor suits that can punch enemies and hover while dashing.
In BYE-BYE BOXBOY!, the comic Suit Up! depicts Qbby piloting a cubic machine similar to Robobot Armor. The comic ends with him turning around to find Kirby in his own Robobot Armor watching him.
In Kirby: Planet Robobot’s final cutscene, it is shown that the Robobot Armor is sentient (or may even have a soul), as it frees Kirby to help him return to Popstar and sheds a tear (of coolant) as Kirby floats away. This was a choice made to contrast the heart-erasing nature of Star Dream.
Notes from the ESRB that explain Kirby: Planet Robobot’s E rating explicitly mention the Jet and Halberd Robobot Armor Modes, saying: "In a handful of sequences, players can pilot a ship and shoot projectiles at obstacles and enemy bosses."