It's human nature to ask the question, "how is a computer superior to a person and how is a person superior to a computer?" In science fiction, it's natural to follow up with the question, "how much can we depend upon computers, and what's the limit of their abilities in the future?" Star Trek tackles all these questions in a shrewdly written bottle show that puts a computer in charge of the Enterprise and sends it out for wargames. Interestingly, producer John Meredyth Lucas liked the story so much, he hired himself as the director!
Along with rich Kirk/Spock/Bones interplay, the story brings aboard guest star William Marshall as Dr. Richard Daystrom, a former boy genius who's now grown up. Towering over the regulars and using his James Earl Jones-like diction, Marshall (a cousin of the actor who plays Captain Terrell in The Wrath of Khan) gives Daystrom a unique presence, helping the episode cover for the lack of personality offered by the M5 computer (voiced by James Doohan). Unfortunately, as the episode progresses, it becomes more about Daystrom than the regulars and becomes increasingly talky.
For Lucas, it's a solid directorial debut, though he'd do better with "The Enterprise Incident".
Remastered Version: With the war games and multiple starships, you'd think this one would be loaded with effects; but actually it's carefully written to include only a few, with the original version using recycled shots from previous episodes. Fortunately, what CBS Digital does get a chance to do is diverse enough to be interesting. The episode begins with a space station, with the original reusing the K7 station from "Trouble With Tribbles" and the new version using the design of Starbase 47, a station from the popular Star Trek: Vanguard novel series. Then there's a planet, which in the original is the one from "Operation Annihilate" (making its fourth appearance in six episodes) which is replaced in the new one with a nice looking Earth-like planet. An automated ore freighter is, in the original, just a reuse of Khan's ship in "Space Seed"; in the new version it's replaced with a "live action" shot of the robot ship seen in the animated series episode "More Tribbles, More Trouble". (This ship, with a command module, also appears in the remastered version of "Charlie X"). Curiously, CBS digital also redoes a beam coming from the M5 unit, though I'm not sure what's wrong with the original! The episode culminates with a big battle between the Enterprise and four other ships, which sounds more exciting than it is, with the original reusing static shots of the Enterprise firing phasers, reusing footage of the Constellation from "The Doomsday Machine" and creating a "copy and paste" shot (courtesy of an optical printer) to show the other ships in formation. The upgraded version does better with much more dynamic shots that show the ships in motion, making the battles seem more like Star Wars than TOS could originally offer.