Short answers, pulled from the story.
Last Order: Final Fantasy VII is a 2005 animated OVA that retells two flashbacks from the 1997 game Final Fantasy VII: the destruction of Nibelheim by Sephiroth, and the escape of Zack Fair and Cloud Strife from Shinra captivity. The events are narrated by Tseng, the leader of the Turks. The OVA was produced by Madhouse and released by Square Enix.
Last Order is not an official installment of the Compilation of Final Fantasy VII. It is considered an outside work associated with the series, though it appears in official guidebooks and companion books alongside the canonical entries.
Last Order was first released in Japan on the 14th of September 2005 as part of Advent Pieces: Limited, a special edition of Final Fantasy VII: Advent Children. Only 77,777 copies were produced at 29,500 yen (about US$300) each. The North American release came on the 20th of February 2007 inside the Limited Edition Collector's Set of Advent Children, retailing for $49.95.
Last Order: Final Fantasy VII was directed by Morio Asaka, with Tetsuya Nomura serving as supervising director. Nomura, the character designer for the Final Fantasy VII series, held authority to approve or reject concept drawings throughout the six-month production.
Fans objected to changes made to the Nibelheim event, one of the most significant backstory moments from the original 1997 game. Hideki Imaizumi, producer of Crisis Core: Final Fantasy VII, confirmed the team received "considerable negative feedback." As a result, the Crisis Core team reanimated the scene and deliberately avoided repeating the choices made in Last Order.
Takeharu Ishimoto composed, arranged, and produced the score for Last Order, including its ending theme also titled "Last Order." The music was released on a combined soundtrack with Before Crisis: Final Fantasy VII in Japan on the 19th of December 2007, with tracks 13 through 27 on the disc containing the Last Order score.