Win - 35G (Original Achievement)
The key to doing this easily, is to make a "save" at the beginning of every zone or act. If you think you did terrible by losing too many lives and could do better, then reload your save and try again.
In dealing with the Final Bosses, start off by making a "save state" so you can do this non stop until you win. 1st Phase: This fight is against what appears to be Metal Sonic, as he is dropping in, if you're fast enough you can get under him and just in front of his feet and spin dash to hit him 4 free times before getting away from him. Be ready to jump over his dash attack and avoid the spines on his back. 2-3 more hits on him should finish him easily. SAVE. 2nd Phase: Robotnik gets into a giant robot of himself. Watch his hands one wrong move and you die, wait until they are back enough and attack his stomach. After a bit he'll blast off and try landing on you. Get on the right side of the screen and wait until the target locks onto you before running left to dodge. If you're fast you can land a free hit as he lands. Around now you should run all the way to the left side of the screen to dodge his rocket punches (2 of them). That is all that you need to know, just repeat until you down him.