There are five movements:
The first movement is Haydnesque, though Haydn turned on his head. Doesn't this first theme look like a Haydn theme turned around backwards?
The trill on the G flat is just the first of many gestures telling us not to take this music too seriously. The second theme, a belching intro by trombones followed by a rather brittle theme in the stratosphere on piccolo, is even more giddy. Shostakovich is one of the very few composers capable of being really humorous, though it is heard by many listeners as grotesque. This first movement is silly, charming and grotesque all at the same time. He achieves these effects by odd orchestral blends and juxtapositions--such as the trombone and piccolo. I once heard a duet for tuba and piccolo and just the two instruments checking their tuning caused the audience to break out laughing.
The second movement is a kind of eerie waltz that slithers back and forth, but in B minor, a very remote key from E flat, the key of the first and last movements. The third movement is a tarantella, whirling along in B flat. It leads without pause into the fourth movement, which is a short transition to the last movement. It has a funereal cast, alternating between blasts on the brass instruments and delicate, arioso solos for bassoon. Without pause we launch into the last movement which recalls a bit the mood of the first movement. But this time the main theme moves by step in a combination of diatonic and chromatic scales.
I must confess a preference for shorter symphonies, like this one. I appreciate the ability to write crisp, light music like this--it is less common than you would think. Now let's listen to the music. Here is Georg Solti conducting a live performance: