Not really obscure, in my opinion. It was pretty much one of the early titles for the system in the US and it was covered in the list of upcoming games in the black Nintendo Player's Guide book, which was about the most pre-release hype you could get considering the book was available for sale before the NES itself was. I remember seeing it get basic coverage in books like "How to Win at Nintendo Games" as well, so distribution certainly couldn't have been THAT bad.