Complex sentence: The anime series was originally released as two films and four OVAs, Recent releases combined a film with the OVAs: four episodes in one release (2x1h, 2x30m) and six episodes (6x30m) in an other.
Split into simpler sentences: The anime series was originally released as two films and four OVAs. Later releases combined a film with the OVAs: four episodes in one release (2x1h, 2x30m) and six episodes (6x30m) in an other.