Really? As if Sonic 2 wasn't a massive release for the console worldwide? It's an honorary Western-developed title at best, since it plays nothing like a Western release.
In my opinion Japan seldom cares what "worldwide" thinks, and they are touchy about such things as the developing location. From the records of the developing process, it becomes clear that there were constant frictions between the japanese & western parts of the Sonic 2 team and Naka himself was depicted as arrogant and unlikable by the other side, an entire stage designed by the western part was scratched. So yes, I'm surprised that the second Sonic is on that list, while the first is not featured at all.
But maybe Sonic is one of those exceptions, which the western market recognized more, than its homeland. Rolling Thunder was such an exception, consequently Namco released the 3rd exclusively in the US. Power Strike 2 and a lot of other Master System releases never hit Mark III. The western Neo-Geo fanbase was granted with the Metal Slug 3 release (thanks Shawn) and subsequent Playmore english versions. Finally, Sonic was launched in the west, the japanese version came last, though slightly improved.