It's interesting to see how Mecha Sonic's design was refined compared to Yamaguchi's earlier sketch: Spoiler One curious detail is that Mecha Sonic's hands went from being Mickey Mouse-ish like Sonic's, to something near identical to Metal Sonic's. It's been said that the Sonic CD and Sonic 2 staff came up with Metal Sonic and Mecha Sonic independently, unaware of what the other team was doing. The Sonic CD staff were surprised to see Mecha Sonic in a prototype Sonic 2 ROM, so they mailed their Metal Sonic designs over to the Sonic 2 team. So did Yamaguchi like the look of Metal Sonic's hands and incorporate them into Mecha Sonic's final art, is it just coincidence, or is there an inspiration that both designs were drawing from? EDIT: Corrected image URL.