I only recently learned that there were two Ghostbusters 2 video games for the Nintendo Entertainment System. I learned about this when I started putting together the video game section of this website. One game adaptation was released in North America, created by Activision, and the other was released in other parts of the world, and was created by HAL Labs.
And now Ghostbusters News has released a mini-documentary about the two games, Ghostbusters II and New Ghostbusters II.