Technical difficulty is always going to different to each individual. A sonata that might be considered as quite challenging to one individual might actually not be perceived to be so difficult by another. I play quite a few of Beethovens sonatas and have ranked the ones that I play in order of difficulty from easiest to hardest.
Sonata in G no 20 op 49
Sonata in G Minor op 49 no 1
Sonata in G no 10 op 14 no 2
Sonata in F Minor no 1 op 2 no 1
Sonata in C Minor (Pathetique)
Sonata in D (Pastorale)
Sonata in Eb (The Hunt)
Sonata in Eb no 4 op7
Sonata in D Minor (The Tempest)
Sonata in C# Minor (The Moonlight)
Sonata in F Minor (Appassionata)
Sonata in C Major (Waldstein)
When it comes to his hardest, most will say the Bb Hammerklavier which is certainly exceptionally difficult however I actually think his Sonata in C Minor no 32 op 111 is also absurdly difficult and personally I would say this is more challenging than the Hammerklavier. It’s also a rather bizarre sonata! Very tricky to figure it out!
For a pianist who is intermediate and can play to a decent standard and wants a Beethoven sonata that’ll impress I’d suggest the F Minor no 1 op 2. The Pathetique may be manageable to some but the first movement really is quite challenging. The rondo on the other hand may more approachable.
Topic: L. V. Beethoven's '32 Piano Sonatas' Ranked In Order Of Difficulty