After reading the reviews, I expected "Love at Large" to be an almost surreal experiment in film noir, heavy on atmosphere and short on plot. It's true that the cars and some of the costumes don't seem to fit the early 1990s setting--Doris's green, full-skirted dress, complete with eight inches of yellow crinoline, is straight out of the 1950s, and the Blue Danube nightclub seems to belong to an even earlier era (pre-World War II). The vampy Miss Dolan exudes a 1940s glamour and mystery, the kind of woman who never existed outside of male fantasies. But much of the action (or conversation) takes place in realistic settings--upper-middle-class suburban houses, airplanes, airports, a ranch in what appears to be Wyoming or Montana.
More to the point, the subplot surrounding the bigamist Frederick King/James McGraw (Ted Levine) is not merely "thrown in," as some critics have suggested. Mistaken identity is a classic comedic device going back at least 2000 years to the New Comedy of Menander in ancient Greece, and it still works. It also adds suspense; both Harry (Tom Berenger) and Stella (Elizabeth Perkins) believe McGraw/King to be Miss Dolan's "charming but dangerous" lover, Rick, and are consequently oblivious to whatever danger the real Rick may present.
The Levine subplot also provides opportunities for variations on the love theme so blatantly emphasized by Stella's omnipresent "Love Manual." Compared with most movies of the 1980s and 90s, this one has relatively little sex but lots of kissing. (Ted Levine gets to kiss two women, unusual for him, but this film predates "Silence of the Lambs," in which his powerful performance as Jame Gumb stereotyped him as a murderer.) There are some genuinely tender moments and a lot of surprises, some of them comic and most of them in some way related either to love or mistaken identity.
The casting is excellent. Both Berenger (despite his gravelly voice) and Perkins are likeable and believable, and Levine is marvelous as a man with two lives and two personalities. (No, he's not schizophrenic; he just likes to go out on a limb because, as he tells Stella, "that's where the fruit is").
To say more would be to spoil the film. Find it and watch it. It will be well worth the trouble of hunting it down.