I am ecstatic that I can go online today and buy so many new games for old systems. Just a few years ago, the only options similar to this at least on the NES were reproduction carts – games that either never came out in the west or never came out at all put on a “donor” cartridge that the buyer generally had to provide, sacrificing a perfectly good game in the process, and having to wait a long time for a “fake” game to arrive in the mail.
This was the reason I once owned a Family Computer, the Japanese version of the NES. Not only were many games different in presentation or mechanics from their American counterparts, but I was able to play quite a few great games that just never made it out here. One of them was a little game called Holy Diver, a riff on the Dio album by the same name, rife with heavy metal references, and highly resembling Castlevania in its mechanics, and Ghosts ‘n Goblins in its gnashing-of-teeth difficulty.
Source: Destructoid Review: Holy Diver Collector’s Edition