Merr Man, there's a reason why the game series is not actually called Far East of Eden, and why I hope people will learn and get used to the distinction. (Look on the box of "The Apocalypse," for instance, and you won't find Far East of Eden written anywhere.) That's because it's not based on P.H. Chada's book. The story is that he, the "author" of "Far East of Eden: Ziria" collaborated with the developers to bring his English "book" to Japan in game form, through the Tengai series.
So that's how the Tengai series of games was born. When "Far East of Eden" appears in the title of the game, it means that this particular title was inspired by P.H. Chada's view of Jipang. (Not all of them have this label in the title.)
Since "The Apocalypse" is not about the history of Jipang, it is not called Far East of Eden. Oriental Blue: Ao no Tengai, is also part of the Tengai series, but does not take place in Jipang, and thus does not feature the name Far East of Eden either.
As for "Far East of Eden" games that haven't been remade, there are several... I believe in addition to Zero and Shinden (Kabuki Klash), Tengai Makyou III: Namida (for the PS2) has never been remade. There's also Karakuri Kakutoden, an FMV battler. If you're talking about the whole Tengai series, Oriental Blue: Ao no Tengai also hasn't been remade. Of brief mention are Tengai Makyou Jipang Seven (the browser game), and if we're really stretching it, "Same Game," if that even counts. I never played it.
I also have this crazy memory of an iphone exclusive Tengai Makyou game with an original story being released years ago, but I can't find pictures or info about it anywhere... I'm not talking about the Ziria remake for cell phones, but rather another game. Maybe it was just planned and canned?
It's a shame that Gaijinworks never got "The Apocalypse" out. I remember when they teased a PSP game a while back, and it turned out to be Summon Night 5. All of the Tengai fans were disappointed. I suppose Konami's in the way of things, since they own the rights to all of the Hudson games, and we know how they are with their IPs.
I was thinking of making a list of things that still remain to be done with the project... Off the top of my head...
1. There's one glitchy text window in the Crane Nation.
2. Graphics after the Peacock Nation are unfinished.
3. Almanac has some issues.
4. Script formatting/revision needs more polish.
5. Battle/Strategy menus need work.
6. Credits aren't working yet.
7. Manual/packaging needs to be fully translated.
There may be more, but these are the biggest things! Judging by DDStranslation's latest twitter post, the initialization and date entry text is completely finished and set to the American date order and time format! Birthdays beyond 1999 are now fully supported, so any teenagers out there who happen to be interested in playing can still play it as intended... I wonder how many teenagers will actually play this, though? Who knows? But they can, if they want to!