Region-free. Will work on UK/EUR/US consoles.
One day, after the defeat of Dr'Robotnik at the hands of Sonic, Robotnik decided to rebuild Eggrobo to travel Mobius to search for the Chaos Emeralds. Eggrobo kidnapped Tails in the Mystic Ruins by sending him into Metallic Madness, but luckily, Tails escaped. He decided to sneak into Robotnik's lab and grab the parts of his robots and pieces. Tails later went to his home in the Mystic Ruins and created a new robot, based off Metal Sonic's classic model, Codename: METAL, with the ability to feel and behave almost exactly like Sonic. Tails was able to track Eggrobo to where he's heading by using his radar, so Tails sent Metal Sonic to Robotic Isle, where Eggrobo was heading to, in hopes to find the Chaos Emeralds and destroy Dr'Eggman's plans once and for all.
Credit: Lone Devil