Frankenstein
It is fitting that I watched this a day after Moonrise. Both films essentially ask a nature vs. nurture question. Moonrise shows a man whose dad is executed for murder and is raised being in equal parts teased and feared that his dad's violence runs in his blood. Frankenstein establishes this in a lecture early at a medical school where the Doctor contrasts a normal brain and the brain of a criminal that he claims is physically deficient. When the latter is put into the monster, the assumption is that he will be violent and is treated as such from the start. The question in both cases is, is the violence that follows a product of the physical characteristics alleged or a result of societally induced self-fulfilling prophecy.
Frankenstein is a more stripped down version of this. Using a simple monster removes a lot of the potential for problematic social interaction that I critiqued in Moonrise. Frankenstein is a dumb brute, instinctually reacting to things he fears or things that threaten him. The scene with the girl is perhaps a tip toward the innocence aspect but the result muddles the message, though is not conclusive in either direction.
I can't claim to have found Frankenstein a tremendous film. I never had any sense of dread because the short run time doesn't really leave room for the atmosphere to develop. It rushes from action to action. I may claim to favor plot to character or mood, but that presupposes the existence of character and mood. This film seems like an exercise in plot absent more than the basic level of the others (though I still find it better than films that have character and/or mood with no more than the basic level of plot so I stand by my preference of story). Since pretty much everyone basically knows the Frankenstein plot at this point, without even reading the book or watching any film version, I wouldn't consider this film very essential.
Bride of Frankenstein
Much of Bride of Frankenstein is stuff that I wish there was more of in the first film. Signs of Frankenstein's humanity when presented with kindness. Room to breath. Yet it feels really odd here. This film in contrast to the first seems almost entirely without plot. I mean, it is called Bride of Frankenstein and we finally meet the titular character at the end. It isn't like the journey there was anything interesting (though you got to give Dr. Frankenstein credit for being just as excited at creating life as the first time). Just a big meh. I think between the two you could have made one recommendable film and saved "Bride of Frankenstein" for a sequel that actually featured the Bride as an active character.