Although Joe Flynn played a serious role, audiences laughed at him. This convinced him that comedy was his forte, and he later specialized in comedic roles, most memorably as the irascible Capt. Binghamton in McHale's Navy (1962).
Lon Chaney Jr. reportedly asked director Jack Pollexfen not to make any dialogue changes or additions after the lunch break, when he usually drank heavily.
The full story of the making of the movie (complete with interviews with some of the participants) plus the script and pressbook are featured in the book "Scripts from the Crypt: 'Indestructible Man'" (BearManor, 2015) by Tom Weaver.
Lt. Chasen mentions putting in a call to a Prof. Dwiggins at CalTech, who may know about Prof. Bradshaw's work. Sue Dwiggins is the real name of co-writer Sue Bradford.
Lon Chaney Jr. has no spoken lines in this movie following the opening scene in his prison cell. His character's emotions were shown through extreme close-ups of his face. Interestingly, that same year he appeared in another horror movie, The Black Sleep (1956), in which his character doesn't speak.