BREAKING: We got what appears to be never-before-seen concept art images from Sonic Adventure 2's development! The images were in a binder at the 35 Years of Speed gallery, which visitors were free to peruse. We grabbed pics of the contents!
#SonicNews
There are 14 images in all, including multiple pages laying out City Escape and pages featuring early ideas and concept images for various gimmicks and set pieces including the trick ramps (pictured here as cars on the road with ramps mounted on the back), the board, and the GUN truck.
We've got a few sample images below, the rest are in an article on our site linked in the replies. I recommend checking out the article: we also go over some of the more interesting details of what the pages say, though we did rely on a machine translation.
We don't often get to post unseen content like this, so we did our best to make sure these images were not previously made public. Hopefully, we did enough!