So I tried the Sonic Adventure style using an old sketch I found in my computer.
Freehanded. Inked. No vector ('click and drag') lines. So line thickness and curvyness isn't faithful to the SA style. Not done in Photoshop (which most SA style tutorials use). Used PaintToolSAI.
Verdict: Not my thing XD I don't think I did the gradient in the highlights right...
Time taken: 4 hours (1 hour sketch, 1 hour lineart, 2 hours colouring). Colouring took less time than expected though
Do not alter or use this artwork without my permission or claim it as your own.