Impressive, but repetitious
I think you relied too much on the D(I think) to end your musical phrases. I also see you repeat the theme quite a few times. I understand that almost all music is repetitious, but most people veil it thickly with variations, dynamics, key changes (a nice and easy one with can produce astounding effects), etc. I loved the syncopation and instrumental variations; add more. A great spot to do this would be before :51... It sounded like your intentions there were to build and then drop away. If you had more instruments, that would be exaggerated.