It's you're game.
Xian, if I sell a game to you, you're free to do whatever you want with it. You can keep it for yourself, you can sell it to someone else, you can burn it, destroy it, or do whatever else you want with it. But if you choose to dump the game or make a mass release of it, then you risk the charges and penalties of a copyright infringement lawsuit.
NGF has the rights, but we're not interested anymore.
NGF can do a mass release because we have the rights for repackaging and distribution (as playmore verified). Our rights are grandfathered in from snk-japan (not from playmore). We are not able to sell or transfer our rights to anyone/company without written agreements from playmore on said transfer. That being said, it would cost be costly.
I am not a lawyer and I am in no way giving legal advice.
Anyone thinking of making a mass release of any game, without written permission from the copyright owners, is risking a lawsuit and possibly paying a heavy fine if the copyright owner pursues the issue. (no matter what system)
Caution is key
In the case of playmore, I would be extremely careful. They took us to court and we did indeed have the written permission. It was just a costly oversight on their part (in our NGF case, playmore is the one that should have been more careful and used a lot more precaution).
That being said, playmore has been releasing games for the wii and playstation store, so they are still actively in charge of their interests, and more than likely they will pursue the matter of infringement.