I enjoyed this! If possible, could you post the score (it'll help us comment on specifics)? I think you did well with beginning the process of thickening a texture. I think what might help improve this piece would be taking a dense texture and exploring ways to reduce it, then add to it, reduce it etc. Moreover, I think that experimenting more with less regular rhythmic configurations will break a bit of the monotony that can begin to develop; pushing a little further will make it feel less like an exercise. Overall, I think you did a good job!