Acting for Two: In The 2nd Runner, Jehuty's and Anubis' A.I., ADA and DELPHI, share the same voice actress. Cynthia Marcucci and Yoshino Miki are their English and Japanese voice actresses, respectively.
Development Hell: The Enders Project, the Zone of the Enders: The 2nd Runner sequel has been put on hold and has yet to resume.
The Merch: Aside from the games and anime, there are wall scrolls, soundtracks, art books, and other products. Special mention goes to the Revoltech figurines of Jehuty, Anubis, and the Vic Viper, as well as Kotobukiya's line of model kits.
No Export for You: Prior to HD Collection's version of Zone of the Enders: The 2nd Runner, a Special Edition of game was released in Japan and Europe, but strangely never to North America. The Special Edition featured some graphical and frame-rate improvements over the original game, new difficulty levels* (the Japanese version has an Extreme difficulty and a Super Hard difficulty in-between Very Hard and Extreme mode, whereas the European version only gets the Extreme mode), new cutscenes and battle sequences, an expanded Extra Mission mode, and sub-weapon tutorials for the VR Training. This changed though as the HD Collection includes the European version of the Special Edition of The 2nd Runner for the North American release.
And there's the two premium editions for the Japanese version of Zone of the Enders HD Edition, which has two books instead of one from the overseas release, and a Blu-ray re-release of the Zone of the Enders: 2167 IDOLOOVA with the most expense of two packages.
Old Shame: Whilst not necessarily ashamed of the original game, the HD Collection's pre-release hype was all focused on The 2nd Runner, with barely a word being said about the HD remastering of the original game; on top of that, the intro specially made for the HD Collection only focuses on the original game for roughly a minute and a half, with the remaining four minutes focusing on The 2nd Runner.
To make things even worse, the Hexa Drive patch on the PlayStation 3 version only addresses the frame-rate issues of The 2nd Runner and enhanced its visual quality to 1080p; the original game is left untouched. Granted the original Zone of the Ender's frame-rate wasn't as botched as its sequel, High-Voltage Studios only enhanced the games for 720p when these games were supposed to be in 1080p.
Same Content, Different Rating: Both ZoE games on the Playstation 2 received M for Mature ratings in the US, despite having precisely one bloody scene each between the two of them, no profanity, and no sexual content. When the HD Collection came out in the US, the version without the Metal Gear Rising demo received a somewhat-more-sane Teen rating.
Vaporware: The PlayStation Vita version of the Zone of the Enders HD collection has been announced at the Tokyo Game Show in 2011 and no word has been said regarding it since.
What Could Have Been: Several design sketches show unused designs for some of the frames. For example, the Raptor was initially supposed to be dual-wielding katana-like weapons, instead of having them grafted on to their arms; as well as unused names for most frames, if the HD Edition's Special Art Book is to be believed, at least. For example:
Jehuty went through several name changes, from New Eden to names such as Exodus, The Whisper, Vision Divine, Lightning and Megadriver.
Similarly, Tempest had the names Faust, I-Vanvo, Epusutain, Vadourv, Devionario, Manonresco and Volpone before settling on Tempest.