Mike D'Angelo’s review published on Letterboxd:
Funny how your imagination will sometimes cling to stuff you invented. I first encountered this film's bizarre premise almost 20 years ago, back when I was compiling Time Out New York's weekly calendar of rep screenings; having grown up in suburbia, I pictured Lancaster there, hopping one fence after another along a single block, or maybe several. Never occurred to me that he'd be doing much more hiking (okay, "portaging") than actual swimming, or that the homes in question would mostly be wide-open estates practically in the middle of the wilderness. So it took me a while to shake off my false conception and recognize what The Swimmer is actually up to, which is far more daring and surreal than I'd gathered from (probably) the Maltin Guide blurb. Only about midway through did it finally dawn on me that Ned is traversing time much more rapidly than he is space, and that what had seemed like a simple portrait of fading virility is in fact radically condensed downward mobility. Cheever handles this beautifully on the page (I read the story immediately afterward), but I'm inclined to argue that it works even better over the course of a feature-length film, with more breathing room between subtle suggestions that various details of Ned's life have altered since the last pool. The Perrys' one significant mistake is introducing brief dialogue and quick glances suggesting that those assembled at pool #1 know something about Ned that we don't, and that for some reason he doesn't. This approach implies that Ned is in denial about unfortunate events that have already occurred, rather than (as Cheever designed it) that years of Ned's life elapse over the course of an ostensible single afternoon. (Significantly, Ned's wife, Lucinda, is present in the story's opening, and clearly hasn't yet left him.)
The conceit comes across anyway. Some of it's in Lancaster's performance, which starts out all swagger and grows ever more pathetic; I got worried for a moment when Ned's former babysitter confessed her teen crush on him, fearing ickiness, but the movie treats his subsequent desperate entreaties with the revulsion they deserve. The rest of it's in the filmmaking, with Perry employing a style that's now so permanently out of fashion—more so even than silent-era formal devices, which do at least occasionally get resuscitated by the likes of Maddin—as to look retroactively bracing. Gauzy filters, blurred focus, multiple superimpositions: Indirection is the watchword, a perfect visual correlative to the script's chronological slipperiness. Granted, individual scenes are hit-and-miss, with some stilted performances among the many supporting players and a few overly melodramatic confrontations. (Also some painfully on-the-nose dialogue, as when Ned asks the nudists "Why is that tree bare?" and then opines that it must be blighted.) But Cheever's idea is so powerful, and the Perrys generally realize it so skillfully, that such hiccups feel all but irrelevant by the elemental finale, in which we leave Ned pounding at the barren threshold of the good life he remembers.
(I later expanded the above into a full-fledged A.V. Club review.)