Nadia: The Secret of Blue Water

Gainax, the production company, has a reputation for being frugal when it comes to animation in some of their productions. This sometimes means that they will reuse animation; not only from the current production, but from other series they've produced if the budget becomes too tight. This is apparent in one episode of this series - when the Nautilus is doing battle against a pack of Garfish, footage of missile tubes opening is lifted from Gunbuster (1988). Also, stock footage of the ocean waves beating against the sand from the Island episodes and the explosion caused by the Tower of Babel's energy beam in this series ends up being used again in Neon Genesis Evangelion (1995).