Way back in my early teens, when TNG was originally airing (and when its first-season episodes were about all I knew of the show), this one was one of my favorites—and even now, while it can’t compare to the Bynars episode (this season’s one actually solid offering), I’d call it a contender for the season’s second-best. Weird temporal phenomena are always an interesting hook, and although this episode’s non-linear time stuff isn’t terribly clear or even ultimately very pointful, at least they were trying to do high-concept sci-fi stuff—and the scene where Data, Riker, and Picard meet themselves (see above) has always been good for a chuckle. Of course, the “we need to shut down the experiment, but the lab is rigged up like a deathtrap with security measures” contrivance makes little sense, and the plot is ultimately resolved in a pretty uninteresting way (“I need to put some antimatter into the thingamabob”)—but points for effort are still in order.
The “Picard’s old flame” aspect of the episode, meanwhile, is actually reasonably well-done in my opinion (although I’ve certainly seen it bashed by others). Near the beginning, when Picard hears the name “Paul Manheim” and reacts visibly to it, the writing is harmless enough to allow Patrick Stewart’s acting to actually shine through; it’s clear that Picard is distracted, feels a bit…unsettled, but it’s nicely underplayed. The fact that Picard is decked out in fencing gear helps, too; it pushes the scene out of the standard, boring realm of “Picard the captain” and shows us a human being caught unawares by the prospect of confronting (as Beverly puts it) a ghost from his past. Picard’s evasive reply when Riker asks if he knows Manheim makes it clear that there’s more to the story, but not in a beating-you-over-the-head, cheesy-setup kind of way. Then, when Picard goes to the holodeck to reflect on his history with Jenice, we get a glimpse of Picard-the-reserved-but-passionate-and-introspective in place of the first season’s usual Picard-the-stodgy-old-man. And when he then decides that he has had “enough of this self-indulgence”—even though the line is indicative of a failing in the character, it feels real (albeit more overt than this trait will be written in later seasons), rather than just being a failing in the writing.
Interestingly, reading the writeup on this episode in The Star Trek the Next Generation Companion by Larry Nemecek, it sounds (to me) as though its writers intended to make a much worse episode than the one they ended up making. Apparently the “love story” between Picard and Jenice Manheim was originally going to be a real love story, with the husband conveniently written as an asshole. Instead, we ended up with a much more subtle treatment in which two people briefly reconnect just enough to reflect on their unfinished business from years ago like mature adults. As I’ve already implied, this humanizes Picard, and I have always reacted favorably to it as a result. (The Beverly jealousy angle is still a bit overplayed, but fortunately it never becomes much of a focus.)
Plus, the episode introduces Picard’s interest in fencing—and opening on a bit of off-duty fun for one of the main characters was an all-too-rare tactic this season and very much welcome on the rare occasions when it was used. All in all, then, this is a reasonably-good-for-first-season episode.