Capcom Generation Volume 2 is a G'NG fan's dream disc. Not only does it contain arcade perfect versions of Ghosts 'N Goblins and Ghouls 'N Ghosts, it also has the Super NES game Super Ghouls 'N Ghosts. There's all sorts of bonus material added as well... remixed music, exclusive art, cast listings for all three games, and more.
The downside is that it's only available in Japan. Sucks, doesn't it?
The PlayStation version was slated to come out here in the U.S. sometime in 1999 or 2000, but was canceled due to two things: Sony's anti-2-D stance and the fact that the first disc, Capcom Generation Volume 1 didn't sell very well in Japan. However, all of the Capcom Generation discs were finally released in the U.S. in 2005, combined onto one disc: Capcom Classics Collection Volume 1 (PlayStation 2/XBox).
Capcom also rereleased Capcom Generation Volume 2 in Japan, on March 30th, 2005; it was retitled Capcom Retro Game Collection Vol. 2, and the official site can be viewed here.