Poor

(listed in no special order. Those below are the ones I'm familiar enough with to list them.)
 

Sky Raiders - Universal - 1941 - poor, non-inventive cues support an otherwise good flying serial--even though the usual group of Universal composers are employed; the cue derivations come from less inspired music from different features.  Of interest here is the inaugural of the helicopter in a serial (as far as I'm aware)--pronounced at that time: HEELicopter.
 

Gang Busters - Universal - 1942 - Grant Withers stars in this usually favorably rated serial, for its plot.  The music is uninspiring, except for the addition--after a several-year absence--of  the "chase" part of "Monster Breaks Out" from Waxman's Bride of Frankenstein. We hear it as amended by Charles Previn in 1939 to end with Waxman's "Chase" cue.  The other cues are repeated enough but do little to attract any attention.
 

The Green Hornet Strikes Again - Universal - 1940 - For some inexplicable reason, this sequel to the first Green Hornet, made earlier in the same year, chiefly uses unrevised classical music sources, most notably the Scherzo from Mendelssohn's Midsummer Night's Dream and the Beethoven Coriolanus Overture. The latter is also employed with the chapter forewords, at a lightning pace compared with its concert performances.  Many stretches of the serial are unscored.   The opening of Schubert's "Unfinished" Symphony is also used--and excessively repeated--just the opening phrases.   We also hear the "Storm" section from Rossini's William Tell Overture--not the part everybody knows (and presumably loves).  It's taken about twice as fast as we are used to hearing it.  Every time we see the front of Britt Reid's mansion, we hear a very short clip from Paul Dukas' The Sorcerer's Apprentice--as we do frequently in the first Hornet.  One misterioso from a feature uses an excess of string tremolos wandering up and down with no defined key signature--something you might hear from hundreds of different movies where no score intensity on its own merits is demanded.  The classical "cues," which I'm used to hearing in a concert hall, do not blend well in this setting, nor do they add the dimension one expects.  There are one or two other feature-derived cues heard briefly on occasion, but not enough to lessen my point.  Finally the serial's title theme, Rimsky-Korsakov's "Flight of the Bumblebee" is also used in the first Green Hornet serial, where its use also in the chapters' bodies makes it excessive in both serials.

Sea Raiders - Universal - 1941 - Another serial with large sections unscored, and when they do have cue accompaniment, it is too often the "Anne Neville Montage," used effectively in the third Flash Gordon serial a year earlier, but wearing it out for listeners here.  The action cues for this first Dead End Kids serial are uninspired.
 

Riders of Death Valley - Universal - 1941 - The "million dollar serial," as the promo literature of the time hyped this 15-chapter western, returning Dick Foran in the starring role from his just previous one in Winners of the West.  The cues are neither familiar nor interesting.  One action cue, also used extensively in the later Overland Mail, incorporates the ascending/descending motive in the first movement of Dvorak's familiar "New World" Symphony, herein accompanying a blast of trumpets.  It wears out its welcome here before we ever get to Overland.

And now our first step "up" to Mediocre Music: