When Lloyd wants to leave after visiting Agnes and her newborn colt, the colt tries to go with Lloyd. That's a mistake: in reality, a newborn colt - or even a colt several months old - will not leave its mother side under any circumstances..
As Ann Westley says, "This program is coming to you through the courtesy of Amalgamated Gas,", the word "amalgamated" does not match her lip movements and is clearly spoken by different voice. (approx. 24:55 into the film, NTSC)
At the beginning of the film, after Austin congratulates Mr. Snodgrass, a shadow of the camera moves across Austin's back.
When Spider swings and misses trying to hit Burleigh, a shadow of the boom microphone is briefly visible upper left of the frame.