Oh, that is cute.
It reminds me that in early concept work and art Sonic was actually supposed to have a human girlfriend who was a singer named Madonna, of all things.
Seeing a people are making custom vocaloids these days, it would be funny to see one based on her concept art.
A link to the scant details about her if you are interested (https://sonic.fandom.com/wiki/Madonna)
In terms of your piece, as I said earlier, this really cute.
I definitely feel you caught the 80's - 90's arcade sensibilities vibe with the background, and little details like the zipper pull have a gold ring make this stand out.
It's honestly hard to speculate on proportion on a figure that I know is innately artificial, but I feel you did fairly well with the musculature, and you gave her fairly runner's legs, which make sense contextually.
Thank you for making this.