You think you’ve got Mozart in New York, with the Mostly Mozart Festival and all? Boy, do they have it here, in the birthday boy’s hometown. For almost as long as I can remember, the Salzburg Festival has been gearing up for Mozart at 250. And at the center of the party are the composer’s complete operas.

There are 22 in all, from juvenilia to that “late” opera seria, “La Clemenza di Tito.” (Nothing in Mozart’s life, sadly, can be characterized as “late.”)

According to the Festival, this has never been done before; the 22 operas have never been put on at one sitting, so to speak. The world loves completeness, or at least its music administrators do. And, this summer, Salzburg is the completeness capital of the world.

Taking the stage of the Great Festival Hall on Saturday night was one of the big operas: “Così fan tutte.” And we had, for the third season in a row, Ursel and Karl-Ernst Hermann’s production from 2004. (The Hermanns are husband and wife.) You may remember my description of this show from two summers ago: large egg (or maybe a rock) onstage; a game of badminton; the continuo player onstage, along with that egg/rock. Etc., etc.

Strangest about this very strange production is that the girls — Fiordiligi and Dorabella — are in on the guys’ ruse. (If I went into the plot of “Così fan tutte,” we’d be here till Wednesday.) And if you have it that way, you’ve ruined the story (nonsensical as it is to begin with). It is as though, in “La Traviata,” you had Alfredo know all along why Violetta was leaving him. What kind of “Traviata” would that be?

A modern European one, perhaps.

In any event, singing ought to count more than a production, and Saturday night’s singing was very good. “Così,” as you know, is a six-man — or six-person — opera. And four of our singers were quite young (as befits their roles); they were complemented by two of our savviest and ablest veterans.

Handling the part of Fiordiligi was Ana María Martínez, a Puerto Rican-born New Yorker. She showed a lightish, flexible voice, and she was beautifully natural in Mozart’s lines. But her big aria, “Come scoglio,” could have used more definition, more spine. The blame there may lie with the conductor (about whom, more in due course).The mezzo singing Dorabella was Sophie Koch, a Frenchwoman. She has all the assets: an inviting, slightly smoky instrument; a secure technique; an impressive musical sense. On top of which, she looks somewhat like Princess Stephanie of Monaco.

In the role of Ferrando was an American, Shawn Mathey. This tenor is sort of made for Mozart, and he did well on Saturday night. The voice is beautiful, the head voice especially so. But, like Ms. Martínez in “Come scoglio,” Mr. Mathey was not so hot in “Un’aura amorosa.” He was soupy and croony, making the aria sound like a pop song — like a romantic standard, actually. Serving as Guglielmo was Stéphane Debout, a French baritone, smooth and confident.

So much for the younger folk; how about the veterans? These were Sir Thomas Allen, as Don Alfonso, and Helen Donath, as Despina, both of whom have been with us, in this production, since ’04. Sir Thomas has plenty of voice left, and plenty of technique. And his tastefulness in Mozart is a continuing joy. Ms. Donath made her Salzburg debut in 1967 — and she sang superbly two nights ago. Really, one had to make almost no concessions. And she clearly relishes the sauciness of Despina.

Conducting this crew was Manfred Honeck, an Austrian who heads the Swedish Radio Orchestra. He did not have that orchestra in the pit, however — he had the Vienna Philharmonic. Whose sound was not very good, and therefore not very Vienna Philharmonic-like. In addition to which, that orchestra was sloppy, which was also uncharacteristic. But Mr. Honeck was competent, on the whole, and will be shown to better effect later.

Two final points, if I may: The Hermanns, or Mr. Honeck, or someone, had the singers pause forever between various lines of recitative. This must have seemed like a neat idea — all realistic and thoughtful.In practice, the idea made for stiltedness, and just plain weirdness.

And a positive note, to end on: You know the sublime first-act trio, “Soave sia il vento”? (Of course you do.) It was outstanding — sincere, unaffected, and like the breeze it describes. Every experienced opera-goer has heard this trio from many great singers, led by many great conductors. I have never heard it better, I swear.

***

Allow me to lurch back, now, to New York and the Mostly Mozart Festival. Christian Zacharias blew in for a few performances. He is a German pianist who created a sensation — certainly in my criticism — last season when he appeared with the New York Philharmonic, as pianist and conductor. He played a Mozart concerto that was consummate, a feat of Mozart playing. He did well on Thursday night, too. But not quite as well as that.

What was he doing Thursday night? Playing an hour-long recital in the Stanley H. Kaplan Penthouse, a Joe Cool spot at Lincoln Center.The starting time was 10:30. These after-hours performances are billed as “A Little Night Music.” Pretty cute for a Mozart festival, huh?

Mr. Zacharias, indeed, played Mozart, and also Ravel. He chose a delicious program, alternating between those two composers. French pianists, and specialists in Impressionism, have long had an affinity for Mozart, too: Think Gieseking, and Casadesus, and Entremont, and others. Mr. Zacharias is a proven Mozartean, and he has a claim on Ravel, too, as evidenced by his victory in Paris’s Ravel Competition (1975).

Befitting such a casual atmosphere, Mr. Zacharias did some talking to the audience, including right off the bat. He showed a little local knowledge. The West Side subway was disrupted that night, owing to flooding. Mr. Zacharias said (and I paraphrase), “Thanks for coming — I take it you didn’t have to use the subway.” A charming remark, and completely unexpected.

Mr. Zacharias then launched into a Mozart sonata, that in B flat, K. 281. For the most part, the pianist was alive and musical, and he brings an improvisatory quality to Mozart, too: He sometimes seems to be composing as he goes, or at least thinking about the music. He is not on Mozart autopilot. In the negative category, he was a bit stiff in his passagework, lacking ideal smoothness.

The second movement has a striking marking: Andante amoroso. And Mr. Zacharias indeed treated the music with loving care. The last movement, a rondo, was lithe, playful, and pretty. (Pretty but not dumb.)

Readers may be aware that a pet peeve of mine is fingernails heard on the keyboard (as in rapid passages). Mr. Zacharias was guilty of this, and it is utterly unnecessary.

After the opening Mozart, Mr. Zacharias played Ravel’s Sonatine, and first had some remarks to make about it: Mozart can appear French, you know (he said); and French composers, e.g., Ravel, felt a plain kinship with the Austrian master.

Mr. Zacharias rendered the Sonatine’s first movement in a refined, knowing way, but his playing was just slightly careful and calculated. Also, he had some trouble with sustained notes in the melody — those notes tended to be dead, unsinging, as soon as he hit them. This was particularly noticeable in the slow movement, one of the loveliest things in the entire French piano literature.

The last movement is a glittering Gallic toccata. Or at least it can be. It wasn’t under Mr. Zacharias’s hands. For one thing, I have never heard this music so slow. For another, it was actually rather dreamy. I don’t claim that it was bad or wrong; only that it was unorthodox, and surprising, and maybe just a tad disappointing.

Mr. Zacharias then treated us to a set of Mozart variations, this one on “Unser dummer Pöbel meint,” K. 455. This has been a fine festival for Mozart piano variations: On Opening Night, Garrick Ohlsson gave us the “Twinkle, Twinkle” Variations (not called that by Mozart, as it happens). Mr. Zacharias played K.455 very stylishly, almost with his hair down. He had gusto, brio, and any other little Italian words you might think of. And it was smart of him to bring this little-known set to the festival.

He closed the printed program with Ravel’s “Valses nobles et sentimentales,” in which Mr. Zacharias was quite Mozartean — rather too Mozartean. He might have contributed more body, more heart, more panache. He was a bit tinkly (not twinkly). He could have used more of the boldness and style of K. 455. But he has his own conceptions, and he did some admirable playing.

One section of this work has a wonderfully rare marking: “Presque lent” (Almost slow). Mr. Zacharias got that exactly right. But in the ensuing quicker movements, he was strangely inward, cautious, subdued. He was perfectly respectable in Ravel’s waltzes, but some of their fun was missing, and virtually all of their thrill.

Mr. Zacharias favored the appreciative lounge lizards with an encore, Schumann’s Arabeske, a little long for an encore, in my opinion, but indubitably an excellent work. Mr. Zacharias played it beautifully and naturally — except for the middle section (the first of two “middle sections,”actually).That was oddly pounded.

Finally, a brief word about “A Little Night Music.” An hour-long recital, no intermission, is a very good idea, and highly civilized. I wonder if the public, during the regular season, would go for such a thing. (You wouldn’t start at 10:30, of course!) It might be worth an exploration.

Salzburg Festival until August 31 (for more information, call +43-662-8045-500).

Mostly Mozart Festival until August 26 (Lincoln Center, 212-721-6500).