Unlike the diverse Sonic the Hedgehog (1993), Sonic Underground had elements reduced, like Garry Chalk does the voice for Dr. Robotnik instead of Jim Cummings since it was considered too malevolently scary, shots of roboticism were cut to minimum, all female animal characters were given clothes since their bodies were more humanly shaped compared to male animal characters, and the potential relationships, which focused on Sonic and Sally on Sonic the Hedgehog, are reduced to minimize romantic interactions. Similar to the second season of Sonic the Hedgehog, elements were devoted to humor and show tones, while darker elements and futuristic violence were minimizes entirely.
That echidna is even dumber than you Dingo.
Dingo: Thank you!
Sleet: On the other hand maybe not!
In the title sequence there is a number of clips with Queen Aleena Crying however one of these clips is played backwards; this is obvious as the tear goes UP her face.