This double feature comprises of Gunbuster and Die Buster (aka Gunbuster 2) condensed them into a single theatrical release told in two parts with a musical intermission in between. The first part, Gunbuster the Movie, condenses the six episodes of the original OVA into a 95-minute moviefeaturing a new 5.1 audio remix and a redub by the original Japanese cast. The second part, Die Buster the Movie, mixes large chunks of the second OVA series with a few altered or newly-animated scenes to create a truncated take on Nono's story.
(Source: Anime News Network)
— Description from AniList community (anilist.co).
