This is a pretty cool idea. However I have a few suggestions. Since you said you're not much of a spriter there is another way to make Generations Classic Sonic sprites with little spriteing knowledge. You could trace the Generations Classic Sonic model like how Metalwario started. This way it saves more time while also looking more accurate to how he looks in-game. I personally think spamdash doesn't fit. He doesn't have that in generations and SA-Sonic already has that. Instead you could give him the overpowered spindash from the consoles version of Sonic Generations. I think this would be quite fun to use to speedrun levels. Since Classic Sonic has a homing attack in the 3DS version and Console version. Nah this is my last suggestion and may be hard to program. What about adding the skill shop from the console verison of sonic generations? Sonic can choose certain skills each level. You could only use one shield per level. You could buy skills from gaining skill points after completing a stage. The faster you complete the stage the more skill points!