I, Monster is Christopher Lee's 1971 Dr. Jekyll and Mr. Hyde, except that the Jekyll/Hyde names have been changed. I wonder why. Peter Cushing is in it, too.
it's viewable online:
Moria thinks it's a faithful version of the story, says the sets are good and praises Lee's performance. 1000 Misspent Hours says that Lee's performance is the film's greatest strength.
HT: Need Coffee