Reminiscent of several other sci-fi stories, but better--more personal, and more subtle. Raises questions in the mind of the viewer all along the way. Steve McQueen and Arthur Hill were great to watch--completely involved in their characters. I would have no problem watching all their expressions and gestures and listening to their conversation for much longer. This episode could easily have been, or could still be, developed into a two-hour feature film, and I think it really should be. It's a great piece of careful, detailed writing, and all the characters were believable (the wife a little less so, a little less fleshed-out).
Shocking twist at the end.
I wish McQueen had quit smoking when he had a chance. Such a loss.
One question remains unanswered: If Martians don't lie, then what about the ones other than Yang...?
I'll definitely watch this again sometime.