The original arcade release of The Idolmaster had several bad endings that were allegedly received by the first location play-testers so negatively that they were immediately taken out of the game. These endings are referred to as Death endings or "Z-ENDs" which can only be seen by earning a Z grade in the evaluation of an idol's performance, and involve the idols having a final meeting with the player to tell them they are giving up. The tone of each conversation varies with some idols frustratingly yelling at the player, while others will appear severely depressed.

The existence of these endings were considered an urban legend among the game's fans until 2014, when a volunteer for the now defunct Japanese game localization website TLWiki found all of the intact Z-ENDs hidden in the data of The Idolmaster SP, and were later uploaded to Niconico. They are listed below untranslated, though archived translations of all the Z-ENDs by TLWiki do exist and are included in the source link:

Ritsuko & Azusa:
https://www.nicovideo.jp/watch/sm24580244

Yukiho & Makoto:
https://www.nicovideo.jp/watch/sm24563142

Ami, Mami, Haruka, Chihaya:
https://www.nicovideo.jp/watch/sm24587397

Iori & Yayoi:
https://www.nicovideo.jp/watch/sm24517297
Contributed by MehDeletingLater