Sonic Advance (7 Emeralds) Part 3: Extra (Moon) Zone
0To access this level you have to beat the game with every character and have obtained all 7 Chaos Emeralds with one character.
If you didn't play as Sonic last, you'll have to replay from Cosmic Angel Zone Act 2 as well as X Zone to see the transition scene, otherwise starting from just X Zone will give you the 'normal' ending.
This boss was harder to hit than I remember, but it's almost impossible to die. Jump with a and dash forward with b. dash through the spheres to get some rings and hit Robotnik's head when it's not covered by his hands. You'll have eye lasers and rocks to dodge, but if you're consistently collecting rings from the spheres then you shouldn't die. You get a different ending for beating this level. I cut the credits out, because they're the same from the other two playthroughs.
So next weekend there's an RPG coming, but I'll also be starting a new game as well some point next week.