Notes:

for context:
“I don’t think SEGA was entirely happy with the eye decision, but these sorts of things you go, ‘It’s going to look weird if we don’t do this.’ But everything is a discussion, and that’s kind of the goal, which is to only change what’s necessary and stay true to the rest of it,” said Miller. “He’s not going to feel like a Pixar character would because I don’t think that’s the right aesthetic to make it feel like part of our world.” -Tim Miller
and a another weird thing is they took inspiration from seth macfarlane's Ted for the Sonic's design (no joke)
Source from IGN