This first movement is classified as one of the most difficult pieces among Haydn's piano works. This is not a technical problem, but a conceptual one. Up to Andante is fine, but the subsequent con espressione is the issue. To put it simply, please understand that this is a piece prone to mechanical execution. Let's consider how to play it in a way that avoids mechanical execution and achieves con espressione.

While it is very important to accurately play the written 32nd notes and triplets, once that skill is acquired, there is no need to continue playing with metronomic precision, or like a programmed synthesizer. Rather, it is a piece that should be interpreted with flexibility.

As one hint, it can be thought of as an opera aria, with the melodic line considered as a vocal line. In that case, if the 32nd notes and 32nd note triplets are played too mechanically, the vocal line itself would sound unnatural. Furthermore, if this piece is considered a string quartet, and the many slurs are thought of as violin bowings, mechanical playing would also be avoided. What would happen if a passage like that in measure 3 were played too dynamically and staccato? And doesn't the phrase in measure 3 require a direction that leads to the melodic line F-sharp on the first beat of measure 4? If so, the dynamics would also change, and playing the second slurred note too energetically and short would indeed result in a truly mechanical performance.

The A on the downbeat of measure 3 is a suspension. And since it resolves to the next G, the G should not be accented, but played softly, as if a violin bow is slowly lifting.

The unit D-E-D-C-sharp-D-E-C-sharp in the melodic line on the first beat of measure 5 also tends to become very mechanical. Establish a direction towards E, and play the final C-sharp so that it fades away. Furthermore, all other passages with many small notes should be played musically and melodically. That is the meaning of con espressione.