I think it does that just fine.

It does. I just can't work out why that's what they wanted to do. The audience is going to either ignore it (for being nothing more than a HD remake of a game they already know), or play the first couple of levels and then stop (satisfied that it's a faithful remake of a game they already know), or play it with The Eye Of Sauron embedded in their head, but a version of Sauron is fixated with the absolute perfect reproduction of every single element of the game, and if the developers get one single thing wrong they will flood the internets with loud and self-important complaints.
The guys making it obviously love Sonic 2, and that's cool. But given that they seem to have some idea about game development, I can't work out why they wouldn't want to spend that time applying their talents to something new that could stand up on its own rather than re-treading old ground for an audience that will react with at best apathy, and at worse complete vitriol.