This should really be listed as "Hamlet (Hallmark Hall of Fame)" rather than as an episode of a television series. (Which is actually true for most Hallmark presentations.) This is a performance of Shakespeare's Hamlet, and not an "episode" of anything.
When this was first shown, Chamberlain, having only recently abandoned the "Dr. Kildare" series, was at the peak of his popularity, especially with young women. I remember the "oohs" and "aahhs" of the young women in my high-school of the time, when they heard that Dr. Kldare would tackle the great Shakespeare. Of course, most guys knew he was gay (he recently admitted it in his autobiography - well, duh, Richard, who woulda guessed?), but in the early years of the '70s, this actually added to his credibility as a Shakespearean actor, at least among Americans. Then, of course, all of our teachers - some of whom were young women, some of whom were gay - ordered us to watch this film, the bard returned at last to the popular arts. (They really wanted us all to forget Zeffirelli's Romeo and Juliet which had included naughty bits.) Of course, within two years Roman Polanski would produce his blood-soaked MacBeth and Peter Brooks a version of King Lear shot as if in the middle of a hurricane - there really wasn't any saving the bard from the 20th Century. The Chamberlain Hamlet thus stands as the last attempt to preserve a middle-brow American classicist approach to this material.
That's a complicated way of saying that the Chamberlain version not only lacks depth, but seems to shy away from it. Chamberlain is actually perfect for the role, but he doesn't get the direction he needs to sound the depth of his character. I watched this about three times, and every time ending up asking myself - "is that all there is to it?" well, of course, there's much more; and occasionally we get from Chamberlain and his fellow cast communicate a sense of the much-more Hamlet involves (especially in the Ophelia sequences), But this is never allowed to develop.
Worth viewing, but perhaps only for the "episode" it might have been.