This is a strong episode, based on a good Richard Matheson story.  He has always been a favorite "TZ" writer.  The show has some weaknesses, like the surprise but actually tremendously risky ending. at least on the part of Walter Van Hass.  Mason Adams, Paul Hecht, Ralph Bell, and Evie Juster were always talented, dependable. and capable veterans of the series, but "Will Hare" above looks exactly like Denis O'Hare, who has really been around in theater, TV, film, you name it.  I wonder if he used the name Will Hare and then changed it?  Anyway, I prefer the story, which was plundered and destroyed a few years back as a film called, "The Box", I think.  It was just awful.  A thought-provoking concept can always be adapted and changed.  If it's a good idea, it will hold up.