Thanks for all your replies :)
I'm going to rewrite the score and in addition rearrange it for trumpet and piano (I picked up the trumpet few weeks ago and it seems that I'm doing pretty well, so I'll be playing this piece by near future) and make some minor changes.
Indeed, there are lots of 1-5 chords, which I, by no means like and don't want to change, as I tried putting some fuller chords and they didn't meet my expectations. I will try to avoid parrarell movements, though. The dissonance that benxiwf mentioned is in fact a little unexpectable and could be done better.
The violin and piano are very simple as I wished my girlfriend, who is rather an amateur violinist, would play this with me when I've learned how to play piano. :) It wont happen so quickly anyway, I dont have one yet, but hey, its good to have some plans for future:p
I did look at some masterpieces, being seriously inspired by Shostakovich's works (my favourite piano trio No.2) And my later works tend to be rather more complicated. I hope you'll find them more enjoyable and interesting.
Cheers, Maciej
PS - should I paste my other works (when I fell they're finished) here, or make a new thread?