Stille Reue (for string quartet)

I'll tell you what, I really want those first 15 measures to senza vibrato. I think that would make the opening really powerful and ready to move into brief middle section. 

I would really consider exploring tempo and rhythm a bit more. I know you vary it up a bit in the middle section, but it really starts to drag a little bit and doesn't feel like it's moving anywhere. This becomes particularly obvious when  you move back into the opening material to end. I think you have a strong idea, just needs a little more work.

Hmm, I think this is a piece with a lot of potential! However, I think in terms of how the harmonies are stacked I think there is more room that you could worked with, quartal and quintal harmonies would have been great! I feel that in addition, I know that this is a slow piece which will not be properly rendered on a midi, but I do think more momentum and a drive should be present. It feels a little draggy and something like exploring more interesting rhythms can be executed well. In addition, I think a powerful melodic line that can fit the melancholy of the opening could be iterated, as the A section feels a little underwhelming. Conversational textures I think can be better introduced as well.

Why half notes? pizz ..?  measure 25.  A very pretty and somber melody.  An Elegy?  I think you could develop this into a larger work.