Producer Phillip Yordan had some pretty tough days in the early 1970s. Yordan was charged with tax evasion, I believe as part of his relationship with Samuel Bronston and Pierre DuPont. Bronston had allegedly comingled Dupont's money on several of his productions (most notably EL CID and FALL OF THE ROMAN EMPIRE). Bronston was finished by the late 1960s and Yordan would fall later, which may explain the erratic production values of BAD MAN'S RIVER and ROYAL HUNT OF THE SUN.
SUN remains, a tattered quasi-masterpiece, despite Christopher Plummer's rather eccentric performance. One wonders what might have been. No matter, what is on display is good enough for the cheap price of the the DVD. Nevertheless, the quality of the DVD leaves much to be desired. The DVD uses a distracting "baby or royal blue" rather than black for its letterboxing. The interlacing is so bad in some sequences, the film is hardly viewable. The sound is uniformly underrecorded. Surely the masters weren't in THIS bad a shape.
Worth a look for students of history AND of good drama.