Why did I buy this? I don't even know. It was a few bucks on eBay, and I figured it'd be interesting. Out of curiosity, I wondered how the developers would make a text adventure work on a console, much less in Japanese.
I tried looking into the history of Zork in Japan, and it seems like it was only translated into Japanese for the PC9801, where it had a sparse graphical interface along with the text. Strangely, it seems that only the first chapter was ever brought over to Japan - a bit of a gyp, considering it's really just 1/3 of the original mainframe Zork experience.
The PSOne (and Saturn) version of Zork looks a lot like other visual novels for the 32-bit systems, like The Silver Case and Baroque Syndrome, with a faded, barely visible background, with bright white text superimposed over it. It's really only graphical in the vaguest sense of the worse, because you can barely make out much of anything. At least the borders change depending on your location.
At any rate, you have four primary commands - Object, Action, Inventory, and Move. You can use manual text entry with the Action command, but it really kinda sucks without a keyboard, obviously. There's an option for English characters but I'm not sure what it does - it doesn't understand English commands nor does it understand Japanese written in romaji. The Object command will let you highlight a noun in the text, which then brings up a particle menu ("wo", "ni", "de", functioning as "to", "at" and "with" in various circumstances.) This is where the Action command comes in handy - based on the item you've selected, it'll automatically pick all suitable verbs. The Move command allows easy access in any direction, and even shows all available exits. There's an ingame map, as well as a foldout one included in the manual.
It's actually not all that hard to play with a bit of Japanese knowledge. Zork didn't exactly have complicated writing in English, and it's still pretty simple in Japanese. As long as you're familiar with the original game and have a kanji dictionary nearby, you should be set.
Not that there's really anything else to it besides the novelty. It does have a very nice CD audio soundtrack though, which consists mostly of atmospheric noises and various other electronic music. I didn't realize it at the time, but this soundtrack was actually composed by Yuzo Koshiro (along with Motohiro Kawashima, who worked besides Koshiro on other projects.) Since I've never seen it anywhere else, I ripped it and uploaded it for your listening pleasure.
On a side note, the graphical adventure, Return to Zork, was actually ported to the PC-FX, Saturn and Playstation in Japan, yet none of these were released in the US. Given that the standard IBM PC didn't have any foothold in the Japanese market at the time, it seems some publishers would port Western games to the consoles specifically for the Japanese audience, yet never bring it out in their homeland. This also happened with The Neverhood for the PSOne, and Phantasmagoria (known as Phantasm) and Dark Seed for the Saturn.