My 50th Deviation EVER!!! I used FreakyEd's DS box template. [link]
The actual game would include a Story Mode, and a Multiplayer Party Mode, as mentioned on the box. Rated E10 for: Comic Mischief, Mild Suggestive Themes, and Alcohol Reference.
STORY: It starts out with Eggman's messenger radar coming to Sonic. Sonic believes that Eggman is trying to be "King-of-everything-goodyforme" again, but it turns out Eggman needs his help. He explains that his "son," Metal Sonic, has betrayed him once again. To make things even worse, Metal has received several upgrades, and is more powerful than ever. What to do, what to do... Well, Sonic and Eggman put together a team of freedom fighters consisting of Sonic, Tails, Knuckles, Amy, Eggman, Shadow, Rouge, Espio, Silver (oh, joy), Blaze, Shahra, Gamma, and Cream. Now your probably asking yourself "Gamma? Wasn't he destroyed?" or "Espio's the only Chaotix member on the team? What the bloody @#$%!?!?!?" Well, Tails and Eggman find the remains of all the other E-Series robots, and fuse them all together, thus building a second Gamma. As for the whole Chaotix issue, well, Metal kidnaps all of them and holds them hostage, because he needs their detective skills to find the Chaos Emeralds for him, and Espio was the only one quick enough to escape. At the end of the game, aboard the Death Egg, Metal somehow manipulates Amy (love, perhaps?) to do his bidding, and turns her against Sonic and the gang. At the end, when Metal is about to die, he confesses that he isn't the one causing all of the trouble. He explains that Eggman was the guy in charge the whole time, and Eggman becomes furious with Metal for unmasking the whole conspiracy. Eggman then breaks out his latest mecha, the OmniEgg, as Sonic and Metal turn into their Super forms to take take down Eggman.
After beating the baddie, they go through a lame, cheesy ending sequence where Amy and Metal start liking each other, Sonic starts rehearsing some tacky, last minute catchphrases, they live happily ever after, bla bla bla, the end.
But ML, you said you would drop the lame, over-the-top storylines!!!
It may seem stupid at first glance, but once it's made, you will see that Sonic will actually be genuinely funny for the first time ever, and the storyline won't seem as cheesy in-game, unless it's one of the parts where it's intentionally campy.