Its all original artwork and animations. Of course, the characters themselves aren't original. Nor is some of the clothing: for example, Miki's gingham shirt from the novelization cover is making an appearance in CCR (because it's hawt)

Viperchan is keeping it as authentic to the original as possible with similar art style and coloring to CTR. I've seen quite a bit more than he's shared publicly and its quite impressive. (I'm helping with the story and script.)