If you can get over the fact that (1) it's 45 minutes long (as all season 4 episodes were) and (2) it's a straight up comedy, you will find one of the most dastardly underrated episodes of the entire run of TZ.
Unlike most of the funny TZ episodes, this one isn't too goofy, zany or over the top. Additionally, the only typically surreal TZ aspect of this one is revealed very early on, when Moomer conjures up William Shakespeare (via black magic) to enlist him as a writing collaborator. This, to me, is very much a "writer's episode," not only in the sense that it's actually *about* writing but that it's very conceptual (kind of like one of those bizarre SNL sketches that airs ten minutes to midnight) and dialogue based. A lot of the humor is aimed at the ridiculous nature of Hollywood TV execs (which was a problem even then but has gotten exponentially worse since) as well as the craft of acting in general. The best scene, for my money, occurs when Shakespeare drops by a rehearsal of his new show to make sure his words are being done justice and a very young Burt Reynolds puts in a funny performance as a Brando-esque method actor.
This episode really shows that Rod Serling could write comedy when he put his mind to it. The whole thing could have been expanded to 90 minutes and might have made a very nice comedic film. I'm not the first person to note this but it would seem that the film "Bill & Ted's Excellent Adventure" took quite a few cues from this episode. I love that movie, but the similarities here are not even subtle.
I heartily recommend this episode to anyone who loves good, subtle, old fashioned comedy. The writing is great and the casting is just perfect, all the way down the line.