Octaves faster than a speeding bullet. Chords more powerful than a locomotive. Able to leap broad keyboards in a single bound—and land nimbly where’er she wants. Pianist Yuja Wang isn’t Superman, but the playing of this 24-year-old phenom—softer, louder, fleeter, faster—is surely supersized and supercharged.

And the program she offered a University Musical Society audience Sunday afternoon at Hill Auditorium, heavy on Russian repertoire, was an apt showcase for her bravura technique. Whether that program—which also included Spanish-themed pieces by Albeniz, Debussy and Ravel and a Beethoven sonata—made for wholly satisfying listening was another matter. When she reached her fourth encore, Gluck’s “Melodie” (“Dance of the Blessed Spirits”), in a Rachmaninoff transcription, you had a hunch it was the last piece: she finally got around to demonstrating her lyrical side, one that was rarer than kryptonite during most of her program.

Wang plays from a center of stillness, and it’s a beautiful thing to watch: Even when her hands are a blur of motion, she makes it all look easy. But on Sunday, that ease did not always undergird emotionally satisfying readings.

That was particularly true in the first half of her bill. Having changed the order of her program, she opened with Beethoven Op. 27, No. 1, playing its pianissimo chords with a remarkable hush and the answering runs with a velvet touch. But her playing seemed overly studied, and the work’s wit, as it exploits shifts of register and dynamics, was largely overlooked. Her Spanish set—Albeniz’s “Triana,” Debussy’s “Soiree dans Grenade” and Ravel’s “Alborada del gracioso”—was technically remarkable but dry.

Really, it was Wang’s Rachmaninoff set, of three etudes-tableaux and the Elegie, Op. 3, No. 1, that carried the first half. With playing titanic and ethereal, Wang fully conveyed the emotional eddies and tides of these works.

There was more repertoire from Russia with love to come: an entire second half of Scriabin, in which Wang really found her footing emotionally. The melodic line of the B Major prelude (Op. 11, No. 11) sang over a rippling left hand; the B Minor prelude from Op. 13 seethed with fierce, seat-raising energy. The G-sharp Minor prelude (Op. 8, No. 12) was moonlit and luminous, as was the Poeme in F-sharp Major. The G-sharp Minor etude (Op. 8, No. 9) was volcanic and tender by turns. She finished with a stunning reading of the mercurial Sonata No. 5.

Or did she? Four encores followed, substantial enough that they seemed an extension of the program, and perhaps an extension designed to rebalance the heavy emphasis on knuckle-busting repertoire.

They did that, to an extent. No one would call the Prokofiev “Toccata,” her first encore, easy work (or even encore material), though Wang did make its repeated notes seem like child’s play. Her transcription of Dukas’ “The Sorcerer’s Apprentice” was similarly meaty and technically treacherous, and showy, showy, showy. Liszt’s transcription of Schubert’s song “Gretchen am Spinnrade” (Gretchen at her Spinning Wheel”), followed, but the playing was more driven than lyrical. Finally, Wang’s Gluck grand finale took us to a more soulful place. It would have been nice to hear more of that Sunday from this astonishing player.