The first section was done well. It almost fits everything into one position and the bowings are nice and parallel. I would just mark the beginning of measure 9 with a down bow to make that transition clearer. In addition, and this isn't necessarily a bad thing, but the way it all kind of fits in one hand makes this first section feel a bit like an etude. Again, not bad but could have branched out a little more.
The second section you might want to mark a few more down bows at the start of every measure, since otherwise the bowings would be unintuitive at the beginning of each subsequent measure. When long phrases are divided (i.e. quarters to eighths, eights to sixteenths), it's nice to start the beginning of those duples on a down bow. Likewise, the lead in to measure 13 shouldn't be down bow if the next bow is also down.
Measure 17 is rough. If you're going specifically for the kind of glide-y, swampy feel, then make sure to mark that, otherwise it looks like poor writing.
Is the mm. 18-25 section all in tremolo? It's better to use the three hash markings on every note rather than having them be marked as such with a long slur. However, I think most players would know to keep tremelo-ing if you put the slur in there (provided you have the more typical 3 hash marking), so maybe it can be used as such in this context.
Hope this helps!