Correction: A previous version of this story incorrectly stated that Sarah Pillow played Mrs.Cackle in “Max and Moritz.” She played Max and Moritz’s mother. This version has been corrected.

The New York Opera Society with the Royal Couple of Norway. (Courtesy of the Royal Palace of Norway)

It was a great weekend for opera-loving children in Washington — however many of them there are. On Saturday, the Washington National Opera opened its newly commissioned “The Lion, the Unicorn, and Me.” On Sunday, the National Gallery of Art presented, along with the New York Opera Society, a double bill of children’s operas: the world premiere of “Supersize Girl” and “Max and Moritz,” which had its world premiere here in 2010. For some children, including the squalling toddler at the National Gallery, this may have been a superabundance of riches, but their parents, and I, probably enjoyed it.

Jeanine Tesori, who wrote WNO’s opera, and Gisle Kverndokk, who wrote the double bill, share some views about children’s opera. It should be short, include different musical styles, and occasionally break down the fourth wall. But their sensibilities and goals are different. Tesori’s piece was touching and all-American, with echoes of musical theater; Kverndokk’s, written with the librettist Oystein Wiik, was European to the core. Where Tesori’s score, for small orchestra, was rousing, Kverndokk’s, written for a chamber ensemble of flute, trumpet, cello and piano, had some of the acerbic wryness of Stravinsky.

The subject matter was also less ingratiating. Max and Moritz are two iconic figures of 19th-century German children’s literature, with some of the anarchic unsettledness of Grimm’s fairy tales or Slovenly Peter: the ultimate naughty boys, who kill nice Mrs. Cackle’s pet hens and buy her a tarantula to replace them. The tarantula bites them instead, and Mrs. Cackle and the narrator, a tenor named Trouble (oh, yes), have the audience vote, through applause, on whether the boys should live or die. No warm fuzzies here.

There was, though, a bracing, scintillating score that was well suited to its subject matter, and a production, by Joachim Schamberger, that also did a fine job balancing on the line between old and new. As Max and Moritz, Carlos Feliciano and Gustavo Ahualli went online to order up a new animal for Mrs. Cackle, their appearance also clearly evoked Wilhelm Busch’s original illustrations — a detail probably lost on many in the audience, since the book is hardly iconic in this country.

Having a double bill of children’s opera is counterproductive: If the point is to write for shorter attention spans, it hardly furthers the cause to present more of it. “Supersize Girl” was a pendant to “Max and Moritz,” American-based and contemporary: It’s about a teenage girl who, afraid of meeting her Internet boyfriend in person, meets a homeless plastic surgeon named Merlin who performs all kinds of ridiculous physical transformations on her. She learns her lesson; Merlin undoes his work; her Internet boyfriend has already sussed out her real looks and thinks she is wonderful, and we get warm fuzzies after all, but the whole thing is slightly more diffuse, and, after “Max and Moritz,” anticlimactic.

The singing and playing, under the baton of Elizabeth Young, were notably strong. Sarah Pillow, who played the boys’ mother in the first piece and Amanda, the 14-year-old heroine of the second, has a genuinely genre-busting voice, full and vivid. The New York Opera Society also fielded two respectable tenors, Feliciano and John Tiranno, who played Trouble in the first piece, and the Mirror, complete with shiny suit and Bryllcreemed hair, in the second. Ahualli offered a warm baritone, and Victor Benedetti was a competent Merlin. Feliciano, Benedetti and Ahualli also seemed to have fun appearing as a Greek-chorus trio of judgmental schoolgirls — the dreaded “in” crowd — whose music derived from Gilbert and Sullivan’s “Three Little Maids from School.” This reference is probably, alas, lost on most of the under-15 set these days, but was one more example of the kind of literary-musical wit that made this double bill a sometimes dense but genuine enjoyment — at least, for adults.