Star Trek: Harlan Ellison's City on the Edge of Forever collects the five-issue miniseries, based on Ellison's original script for the episode. I'm an ardent Star Trek fan, though less fluent in "The Original Series," and though I'm familiar with the televised "City on the Edge of Forever," I didn't re-watch it until after I'd read the comic. I can therefore state that as a Star Trek fan, but with neither a strong background in "The Original Series" nor "City," I still enjoyed this collection very, very much.
Writers David and Scott Tipton, working from Ellison's script, capture exactly the character's voices; I very much felt like I could hear Kirk and Spock, and moreover William Shatner and Leonard Nimoy. Artist J. K. Woodward does an exceptional job not just making the characters look like their television counterparts, but in replicating the nuances of the actor's faces -- Nimoy's raised eyebrow, Shatner's bemused half-smile, and so on. Ellison's script specifically deals with more mature material than the average Star Trek episode, one of the reasons it didn't air as is, and this helped hold my attention when the sometimes-campy "Original Series" doesn't always do so.
[Review contains spoilers]
One of the biggest and most immediate differences between the City comic and the episode that aired is that Dr. McCoy plays almost no role now, and certainly does not accidentally inject himself with a psychotic drug and hurl himself into a time-travel portal. The culprit is Beckwith, an Enterprise crew-member and apparently long-time drug-dealer, who murders one of his buyers and then escapes through the time portal to get away. Why this script wouldn't have worked in canon is therefore immediately apparent, given the idea of a long-standing drug culture on the Enterprise that Kirk and the senior officers weren't aware of. At the same time, the radical wrongness of this plot development immediately endears the story to me, because it's the exact edginess that Star Trek, in all its forms, usually lacks.
I don't feel strongly about this, but I can see how having McCoy involved in the story gives it extra resonance. Said resonance doesn't play out in the episode per se, but I know I've seen a couple prose or fan-fiction stories dealing with the aftermath of "City" in which the Big Three confront their shared guilt over the incident -- McCoy, for sparking the mess; Kirk, for falling in love with Edith Keeler against everyone's better judgment; and Spock, for advocating Keeler's death from the get-go. In reading, I still love the idea of drug-dealing on the Enterprise, but for historical value I like this as a "triumvirate" episode.
Of all the other differences between the two works -- the general appearance of the Guardian(s) of Forever, an increased role for Yeoman Rand and less so for Scotty and Uhura, and other minor items -- it's therefore maybe a little surprising that the upshot of the story is essentially the same. Kirk still falls in love with Edith Keeler, and Kirk must ultimately let Keeler die, hit by a truck, in order to preserve the timeline. In reading the book, I didn't expect any difference here, so I was not disappointed that the story unfolds as it does, though I see in looking at IDW's publicity for the final chapter that they teased "you only think you know how it ends!" Well, if you know how it ends then you do, indeed, know how it ends, though again that didn't diminish my enjoyment.
Ellison and the Tiptons also include a healthy dose of Depression-era ethnophobia in the story, which again I felt was nicely a mite more biting than what you'd find in your average Star Trek episode (not discounting, however, Deep Space Nine's "Far Beyond the Stars"). This leads, in the third chapter, to a Star Trek-esque philosophical conversation between Kirk and Spock as to whether violence is endemic to humanity or a natural phase in the evolution of all cultures; here, too, I enjoyed the sense that the writers took Kirk and Spock's trademark antagonism farther than it might ordinarily go.
The story comes back to those themes of violence toward the end, first in the character of Trooper, a homeless World War I veteran and amputee who helps Kirk and Spock find Beckwith, and then who sacrifices himself to save Kirk's life. Even as Trooper has been a "warrior," of sorts, he has within him the selfless good that Spock suspects humanity lacks. (The sequence of Trooper's death, toward the end, is one of the few places the writing and art misfire slightly, with Kirk and Spock looking around at it's not clear what for a couple panels. Also, one of the book's final panels has Kirk looking out an Enterprise window, and possibly he's meant to be screaming or crying but here, too, it's not entirely clear).
Finally, in this different version is it Beckwith who tries to save Keeler's life, leaving Spock confused why a bad person would do a good thing. There are extenuating circumstances the story doesn't acknowledge, like the already-established fact that the shifts of time would unconsciously draw Beckwith to Keeler, but ultimately Kirk is able to show Spock that humanity is not one thing or one emotion. The painful implication for Kirk is that while Beckwith did an uncharacteristically good thing trying to keep Keeler alive, Kirk did an equally "bad" thing not preventing her death, even if for the greater good.
From a writing standpoint, even as Kirk finds himself a different romantic partner every week, I thought the writers did well in making Keeler believably different, special, and worthy of being Kirk's "great love" in the span of a few scant pages. In this way, IDW's Star Trek: Harlan Ellison's City on the Edge of Forever is additive to the legend of the episode and fleshes it out such to enhance the value of both. Accessible and self-contained, this is a fine gift for a Star Trek fan and a worthy diversion for a long afternoon.