Neo-Geo Forums

Hey guys. So as I mentioned before, I have been a big fan of Neo Geo games for a long time. But not until very recently, did I know about “Dog Tags”. I was watching a video on YouTube where a guy was showing his Neo Geo collection. Then he was asked which of his games were pricy and he showed Ninja Commando saying it’s expensive because it has the Dog Tag. So I checked my games and I found several games with the Dog Tag on them. Why would that tag make it more pricy? Can one game be released with Dog Tag and then also be released without? I would like to know more about this