The Japanese Sonic Geneations: Blue Adventure website has been updated by SEGA of Japan with two new videos. These show level runs through both acts of Green Hill Zone, owing to the length and design of the level ironically Classic is more akin to the original Green Hill Zone than the console version as the user is able to complete it in twenty-seven seconds.
You can check out the videos below:
Act 1 – Classic
Act 2 – Modern
[Thanks to Woun of Russian Sonic Scene for the tip and the videos]