Hello there
I have to say, there are some very interesting ideas/motifs used in the piece. Good job with that. You also are able to evoke different moods through the mellow/jazzy opening, frantic 16ths, and phrygian-sounding "march".
As a clarinetist, I can tell you a few things:
Remember that in order for a clarinet (in Bb) to play concert pitch, it must play a written major second above. So while (currently) the piano plays in C, the clarinet is playing in D. I'm sure you know this, but, depending on the skill of the clarinentist in question, some of the runs may be too challenging. Keep that in mind.
Also, the clarinetist seems to be doing all the work here. Pianists can breathe whenever they want, so maybe you should consider easing up the clarinet part and giving some more material to the pianist. After all, even though the piano is accompanying the clarinet, it's really still a duet. And this will also give the clarinetist so time to breathe.
Great work.
(and I've attached your midi file as well, sequenced by NWC)