Very good work
Suggestions:
Op.26 C min. only suggestions are that the slightly different sections at about1:45 (arpeggios) and 2:03 (triplet chords) aren't blended in with the piece as well as the other sections. They maybe feel slightly out of place, but they add variation to the piece, while mostly remaining in character.
No suggestions for the A minor. Obviously the material has plenty of scope for development, but as it is, a Klavierstück, it doesn't need this. I enjoy the sudden halts throughout, and how they're worked with.
My only suggestion for the E minor is that because it has quite a major feel throughout, the somewhat sudden modulation to the minor at the end doesn't fit in with the overall feel of the piece. But that being said, it doesn't stick out either

And for the Marcia Funebre, I can only suggest that while the modulations through the major are good, and add gravity to the succeeding minor sections of the piece, they perhaps linger too long for a funeral march. But that's just me trying to find something to say about this very good work, lol.
Also, perhaps the ending could be slightly different. More sombre perhaps, or more defined. (As Salieri says in the film Amadeus, "you don't even end your pieces with a big bang, so the audiences know when to clap")
lol. ok that probably wasnt a very exact quote, but anyway.
Very good work!
My favourite are the Op.26 and Op.27 pieces.
Very enjoyable
