Well, this was an idea of mine that I had ever since Kirby: Planet Robobot was announced and it eventually drove me to making a concept with Aozora playing around and fighting bosses in a huge mech, potentially giving a focus on improving the mech and giving it slightly more presence, including being able to bring it inbetween levels. It would also serve as the main platformer installment of Arc 4, which otherwise wouldn't have a classic-styled Aozora platformer.
After Planet Robobot released, I called the concept "Roboforce U.S.A" due to the concept finding itself taking place moreso in the USA instead of Japan. Afterwards, I began to think of a starting plot, and decided on "Guy in the Americas steals seven top-secret humanoid battle robots, luring in the makers of those robots who now rest in space to descend to the planet's surface and obey his orders because he has the blueprints, and proceed a hostile takeover on the country. A rescue team from California who had dealt with this man in the past begin to search around the globe for possible new recruits, and during their search in Japan, they find Aozora and recruit him without question after he gets into a confrontation with one of the seven battle mechs that was leading an invasion there and holds them off-finding a large mini-mech armor of his own in the process that can use Power-Ups."
Part of the plot's characters pay homage to Metal Wolf Chaos (cause battle mechs in the USA) with the "guy" mentioned above being a stand-in for Vice President Richard Hawk- including similar attitude, cockiness, and using a mech armor of his own. The other half of it is based on Azure Striker Gunvolt, with the seven battle robots the villain releases to the world being done in the same style of the Seven Swordsmen and the Seven Grimoires that occupied the two Gunvolt games. They also would play homage to Super Bomberman 2, Super Bomberman 3, and Super Bomberman R, each battle robot having their own giant mecha they can fuse with in one final effort to stop Aozora at the end of each Zone.
There would be a robot for each of the seven colors of the rainbow: Red, Orange, Yellow, Green, Blue, Indigo (instead of Pink), and Violet. Red would serve as the (secretive) leader of the robots and would be the first and last of the robots that Aozora faces (outside of the boss rush), having two mechs encountered in Worlds/Zones 1 and 7 respectively. Red meanwhile also gets a crazy "awakened" form when he is rematched later on. Blue is the second-in-command and is faced in World/Zone 7 before the eventual rematch against Red. The other colors are faced in the second through sixth worlds in reverse order (Violet, Indigo, Green, Yellow, and Orange). As for the main villain, he is faced in World/Zone 8, followed by what may be the total leader of the "robot makers", with a rainbow motif, referring to the robots as "his children".
The names of the seven robots are undecided, though I envision they would all follow a specific theme. (UPDATE: They now have names:)
Red - Wrath - Vauxen
Orange: Glutton - Slourstro
Yellow: Greed - Phasmor
Green: Envy - Morgaous
Blue: Pride - Tarumont
Indigo: Sloth - Roguem
Violet: Lust - Malianta
The man that would unleash them would be named Jonathan.
They would also follow these guidelines to try and make them more unique from the Swordsmen and Grimoires:
*The robots are in their "battle suits" 24/7, versus the Swordsmen and Grimoires that transform from casual wear into their battle suits. (Sorry if I get the terminology wrong)
*Their anatomical structures are slightly less humanoid, while still sporting human-like designs.
*Their faces use artificial human skin, except for Orange and Yellow.
*Their eyes would retain the colored eyes on black sclera look, the explanation being that they're LED lights that slide around the robot's eye socket.
*Their voices are somewhat broken, robotic, and distorted from years of inactivity (though that can't really be shown in art, heh) They can also be deactivated and reactivated by whoever has control over them.
All the robots would be offshoots (design-wise) of their respectively-colored Azure Striker Gunvolt swordsman (i.e. Red/Vauxen = Viper) though Blue/Tarumont would be an offshoot of Tenjian form the second Gunvolt (leaving Indigo/Roguem to be based on the first game's Blue: Merak)
Otherwise, that's pretty much all I got for this idea. Dunno when i'll go around to working on it more.