Not a bad miniature. I love seeing people move out of the box and try something new.
That said, this style -as you can probably attest- isn't easy to compose in. The removal of a tonal anchor removes formulaic structuring of musical material. We are accustomed to hearing music in terms of t-d relationships, harmony that assumes a purely functional role, and melodic contours that fit interchangeably within the aforementioned musical roles. In writing music like this, there's a few things that I've discovered in my own musical pursuits:
1. It's important to give the listener something to latch onto. Your opening 3 measures lay out 3 distinct motivic units coupled together into a short melodic snippet. This snippet is memorable and definitely something one can look for within your textures. When I compose in this style, I've learned to take these snippets and develop them within the texture. This also allows you to venture further into more eclectic arenas by being able to incorporate diverse styles -almost similar to how composers treated the Theme and Variations form.
2. Some techniques are cliche. I hate using the term cliche when it comes to this aesthetic of music. However, I found that rhythm is one of the easiest facets of music to play around with. You can literally make anything sound amazing with the right rhythmic undertones. Oftentimes, many who write this style of music will over rely on rhythm to compensate for other musical deficiencies. As I mentioned above, you have to keep the listener engaged -and when the other musical facets are difficult to maintain... rhythm is an easy go to. That said, I like the rhythmic punctuation in mm. 23 - 34. I also like that it seemed to play with the descendingmaterial from mm. 10-11. However, it didn't seem to congeal with the remainder of the miniature. It certainly isn't a driving force behind it. Perhaps you can transition into this material or overshadow it in the Lento section?
3. Color, Color, Color! Moving away from tonality removes mostly predetermined colorations to the material. We know that the further away from a tonal center, the more tense the music will get. Adding chromaticism also increases the tension in often colorful ways. In this type of music, 'texture' and 'form' become the tools that you'll want to use to bring life and color to your work. It shouldn't just be dissonant for dissonance's sake (though, believe me, I do write works that have that sole purpose). What I mean is that dissonance is just like any other tool. It's something there to add coloration to your material. The bass line beginning at measure 7 is what brings this point up. The motion here seems to move from an ethereal to plodding manner -that doesn't seem to accentuate the right hand. I'd look at perhaps playing with the right hand material in the left hand. Offsetting rhythms, perhaps gentle punctuations of the offbeat chord, or even just suspended contrapuntal material here would bring out that retrograded material in the right hand. Goal is here to add color to your material that fits the material.
I hope these points help. I'd love to see you do more of these and try to push your envelope further in this aesthetic. Nice foray!