Heyah! So will list couple of points:
1) I like the melody sound choice :) i think it works great, tho, i think it could ramp up a bit in the middle. I would say the song gets a bit boring after that part because it loops and in not very interesting way
Also, the melody could use a little volume down
2) as mentioned above, the song doesnt really chane much, for the lenght its given. You could add some changing chorda, make the percussion do a different pattern, make the bass do some different pattern etc.
Even add some new instrument :D
Its a good submission, but could use a lot of work