We're doomed.
Super Duper Metal Sonic is the super awesome upgrade to Super Metal Sonic. Super Duper Metal Sonic was created when Metal Sonic absorbed the data of the Chaos Emeralds, becoming Super Metal Sonic. Then Super Metal Sonic absorbed the data of the Super Emeralds by impaling them in himself. This upgraded him into Super Duper Metal Sonic.
Super Duper Metal Sonic is by far the most powerful form of Metal Sonic, which is in turn a form of Sonic. Super Duper Metal Sonic is a 50 foot tall cyborg-type creature of pure Hell. With this level of upgrade, Sonic's soul is buried deep inside the metal madness. Instead, Super Duper Metal Sonic becomes a complete monster that destroys everything in sight. This is good when the only thing in sight is the Death Egg. This is bad when the only thing in sight is a city full of innocent civilians.
Super Duper Metal Sonic has been used several times over Sonic's history. He is usually used when Sonic has access to the Chaos Emeralds, the Super Emeralds, and the Metal Sonic suit. The idiot does not seem to realize that he could turn into the more powerful and controllable Hyper Sonic with the Super Emeralds.