This was made in 1936, the very first year of Republic Studios after it was formed from three smaller studios. Probably they were searching for how to do it right, and they hadn't quite hit on it yet--the fights and the cliffhangers are not quite up to Republic's later standards. Several cliffhangers have incredible cheats--they must have counted on the kids not quite remembering exactly what happened the previous week.
Speaking of Republic's high serial quality, this serial actually got the soon-to-be-great-director William Witney started in the genre. One of the directors, Mack Wright, was Witney's brother-in-law, who made him an extra, riding in with the Cossacks. He also served as a second-unit assistant director. Two other well-known serial actors have uncredited parts in this: Crash Corrigan ("Undersea Kingdom", "The Painted Stallion") plays Captain Fremont in Chapters One, Eleven and Twelve, and Jack Ingram ("Green Archer", "Jack Armstrong", "White Eagle") plays both a vigilante and a Cossack at various times. At least William Farnum ("Red Ryder", "Undersea Kingdom") did get credited; he plays Father Jose, the Eagle's accomplice. We also get a good look at the all-time greatest stunt man (and director of the Chariot Race in "Ben-Hur"), Yakima Canutt, as an actor--he plays Barsam, the henchman who kills the hero's father and brother in the first chapter and steals the father's ring.
Robert Livingston is suitably dashing as the Eagle, sort of a combination of Zorro, the Lone Ranger, and the Durango Kid, with his mask, black cape, white horse, and whip (Livingston also played the Lone Ranger in two subsequent serials). Livingston has not one but two sidekicks, the veteran Raymond Hatton ("Rustlers of Red Dog", "Three Musketeers", "White Eagle") and Guinn "Big Boy" Williams ("Riders of Death Valley"). Kay Hughes ("Dick Tracy") was considered one of the most beautiful of the serial queens, even though she appeared in only two serials (and lots of Westerns). I had never seen Fred Kohler before, but he's effective as Jason Burr, who lusts to become dictator of a new Russian colony in California--and, one presumes, in charge of all time, space, and dimension, like so many deranged serial villains before him.
