Almost everything else I planned to say has been said by someone else here-- this is unusually zippy for a movie by the normally mediocre Wesley Ruggles, that big lummox Richard Dix is unusually animated and even amusing at times, the production design and cinematography are very handsome (and female leads Andre and Judge ain't bad to look at either), it's probably the only movie in which Edward Everett Horton handles a machine gun (although he does prove pretty handy with a pistol in 1938's Wild Money), and while the movie seems a bit underwritten (or more likely written in 3 days), it's pretty everything you could want from a 68-minute pre-Code B movie.
The other interesting thing I would note is that it could have inspired bits in two much more famous movies-- the whole opening, in which news of a bandit's rampage is conveyed by telegraph until the moment that the bandit's men chop down the telegraph pole, plays like a dry run for the much more famous and accomplished opening of Stagecoach-- and it's hard to think that's an accident when you know that co-writer, and RKO producer during this time, Merian C. Cooper (of King Kong fame) would soon work with John Ford on The Lost Patrol (as well as on most of his immediate postwar work). The connection with Howard Hawks is less obvious, but when you consider the situation (tough guy Dix surrounded in compound with a bunch of people whose ability to defend themselves is doubtful), and then hear him refer to Arline Judge by a nickname-- the town she was from ("Bridgeport")-- and hear her answer in a deep, insolent Betty Bacall-Angie Dickinson drawl, there's a definite whiff of the much later Rio Bravo, in which John Wayne is holed up with a bunch of questionable help and a girl called Feathers.