The cork on the table changes position between shots when The Wild Bunch is telling Jessie James the robbery plan.
Whenever Manuel Lopez is asked if he speaks English, he always says; "a little" in Spanish, but he seems to understand and speak English just perfectly all other times throughout the movie.
During Dr. Frankenstein's experiments, she uses WWII Army helmets that the tops are painted red and yellow tape is wrapped around them holding some neon tubing.
Contrary to the film's title, it's actually Frankenstein's granddaughter that Jesse meets.