Petropolis Voltage

Petropolis Voltage (ペトロポリス・ボルテージ) is a 2005 action-adventure video game developed by Dimps and published by Namco. It resembles Petropolis 8 in terms of sprite design and gameplay. But the boss characters and stage designs are completely rendered into 3D, creating a 2.5D effect. This game was made in honor of the franchise's 10th anniversary, dating back to 1995.

Plot
Further into the future, the wielders of the Swords of Ancients (from Petropolis 6) were fighting against a cult known as the Cult of Beryl. They have traveled to the past to change the future and remake it in an empire which they rule. Gopher, Topako, Susan, Hornet (a former member of the cult), and Platinum (Zero One from the future) travel to the past in order to stop him. Teaming up with the heroes of the present (Thunder, Bolt, Selene, Soul, and Walter), they set out to stop their enemies from the future. But the Council is not alone as they recruit Whisker and Dr. Gerbil in their cause, and they create the chimeric solders Captain Blubber and Edi to assist them.

Petro Quintet

 * Thunder Storminski: Plays as he does in Petropolis 4 and 8.
 * Selene Melodia: Has her previous elements, including a new one: aura.
 * Bolt Cinnastar: Can perform "ground wave" attacks.
 * Soul Squareshell: Plays as he does in Petropolis 9
 * Walter McBlowhole: Uses Krow to shapeshift into different weapons.

Neo Quintet

 * Gopher Woodrow: Uses his psychic abilities from Petropolis 6, in addition to creating "psychic arrows."
 * Lin Topako: Retains her pyrokinetics, but can also form a "flare baton" for close combat.
 * Susan Richardson: Controlling her dark powers, she can create spikes of darkness.
 * Hornet: A former member of the Cult of Beryl. He joined the cult after being promised a way to bring his father back, but defected after hearing their true intentions. He now joins the wielders of the Swords of Ancients' fight for time. Hornet wields the Turbo Sword of Ancients, granting him super speed.
 * Platinum: The name given to Zero One in the future. He resembles Zero One prior to Petropolis 7, but has been given a paintjob, giving him platinum armor (hence the name). He has joined the wielders of the Swords of Ancients in order to fight the Cult of Beryl. Platinum has no special abilities, but he can fire missiles.

Bosses

 * Cult of Beryl: A shadowy organization from the future. They enforce a dystopian society using their Civil Protection Robots, and later launch a scheme involving traveling to the past to change the future and remaking it in an empire which they rule. They even has Whisker and Dr. Gerbil join them on their villainous schemes.
 * Captain Blubber: A chimera soldier with the mindset of a corporate general. He was created by Whisker and Dr. Gerbil to assist the Cult of Beryl in their schemes to change the Petro Islands. He is often fought by the Neo Quintet.
 * Edi: A chimera soldier who follows the mantra of "silencing those who stand in his way, no matter what they have to say." Alongside Captain Blubber, he was made to help the Cult of Beryl conquer the world. He is often faced by the Petro Quintet.
 * Subaru Whisker: The final boss for the Neo Quintet. He controls the Gigagryph.
 * Dr. Renmaus von Gerbil: The final boss for the Petro Quintet: He controls the Decasquid.
 * Next Eater & Ar' Teri: Two of the most fearsome monsters from the Infernal Abyss. After the defeat of Captain Blubber, Edi, Whisker, and Dr. Gerbil, the Cult of Beryl opened the gateway to this dimension and released these creatures upon the Petro Islands. Both factions of the heroes tried to stop them, but to no avail. But with the powers of the Sacred Orbs and a certain few morphmen, they stood back up and took on new forms to defeat the monsters. The Petro Quintet fought Ar' Teri while the Neo Quintet fought the Next Eater.  The monsters are defeated and imprisoned back into the Infernal Abyss. The Swords of Ancients wielders arrest the cult and take them back to their own timeline as the heroes thank each other for their help.

Stages

 * Forest Falls
 * Cobalt Palace
 * Glyphic Highway
 * Neon Park
 * Frontier Canyon
 * Crystal Hills
 * Mystic Fields
 * Meteor HQ
 * Infernal Abyss