Mozart composed this symphony in either 1773 or 1774 for Salzburg. If 1774 is correct, then No. 28 followed rather than preceded Nos. 29 and 30. Like all but four symphonies (Nos. 25, 29, 31, 34) written before his escape in 1781 from the employ of Salzburg's autocratic Archbishop, No. 28 has been overshadowed by his last six symphonies, beginning with the "Haffner" of 1782 (No. 35). Symphonies 28 and 33 (in B flat, K. 319) were written in major keys and deserve a fuller life than occasional performances. No. 28 is more extroverted; typically, Mozart added trumpets and timpani to the usual pairs of horns and oboes (or flutes). For some mavens it echoes (or anticipates) works ranging from Haydn's "Farewell" Symphony of 1772 to his own The Magic Flute of 1791. However, despite comic implications in the scurrying Presto finale, he eschewed ironies and sentiment.
Decorative embellishments throughout are hallmarks of a style Mozart mastered when his father exploited him far and wide as a child prodigy. In Salzburg, Wolfgang came under the tutelary wing of Michael Haydn, who coaxed him to invest his music with deeper feelings than previously risked. Beginning with Symphony No. 25, Mozart responded remarkably. During the slow movement of No. 28, minor-key measures cast shadows on the landscape as if from passing clouds. The Menuetto begins conventionally, albeit with themes of "symphonic" character, but the second subject of the trio (for strings only, marked forte) has chromatic accidentals that intensify expressiveness. So does the use of sonata form in all but the Menuetto movements.
Allegro spiritoso characterizes the first movement in 3/4 time, with its four-chord downward arpeggio before the fun begins in the violins. There's a key change for the longer second subject, plus a brief closing theme in C major. After an exposition repeat, the principal theme not only dominates a short, spicy development, but leads off the reprise and coda, too.
The 2/4 Andante in F major opens with an aria-like, legato main theme for muted violins, but it is the third, closing subject (in sixteenth notes) that occupies a brief development section.
Mozart modifies Menuetto with Allegretto and assigns the horns two five-note measures without accompaniment for the third movement. This is a danceable minuet with oboes doubling both song-section themes for violins.
Nobody but Mozart, even at 17 (or 18), could write Presto finales as insouciant as this one. Craftsmanship is masterly, the more astonishing when it's remembered that this isn't the usual rondo-finale, but sonata form. The violins' trilled main-theme, like the whir of hummingbird wings, is the principal subject of both the development and a brief coda, wherein oboes double the trills -- thrills in fact, given the challenge of Mozart's vivacious tempo.