I have mixed feelings about this image.

First of all I tried to do the same thing I did with the Freedom Fighters, mixing the classic design with the modern one.
So I kept the colors but I give him a more adult and streamlined appearance, I modified the classic "mane" of Manic with a 3 simple quills, and to make him a little different from his brother I give him longer back "hair".
I really don't like the original design od Manic or Sonia, in my opinion they are a bad mix of Sonic and Jem and the Holograms, or, if I'm gentle, Sonic with a wig. A bad, too much human-like (but still fake) wig.
It's a shame because I really like the other Manic's traits, the design is really simple, I expecially like the shoes. Still he looks like a fancharacter or a recolor.

Btw I never saw a single episode of Sonic Underground...