"The Duplicate Man" is a great example of a TV episode that tries to do too much. It's also a great example of a plot that really needed to be polished up before it was made. It's a shame, as the show sure had a lot of promise and could have been exceptional.
The show begins by learning that in the future there will be an ultimate evil creature, the 'Megasoid' but that it was deliberately exterminated by mankind because it was so dangerous. But, almost immediately after the audience hears this, they see that the stuffed dead one on exhibit in the museum is NOT dead but pretending.
In the next scene, you learn that a nasty rich guy, Mr. James, was responsible for bringing this horrible creature to Earth despite it being against the law. Why? We never really know but you could likely assume he did it simply because he could! But, when it escapes and potentially could reproduce itself, he decides to kill it by creating a duplicate of himself--a duplicate unaware of much of anything other than its need to kill the Megasoid. Naturally, it doesn't work out exactly as planned.
The show could have just been about the Megasoid and this might have made a good episode--provided, also, that the creature not look completely ridiculous (which it did). You just have to see it to believe it! The show could have been about the duplicate and the duplicate turning out to be a better man than the original! But that was lost among the Megasoid silliness. Streamlining the episode and making a semi-believable alien (if it would remain in the story) would have done wonders with this near miss.