This is amazing! The blend of live instruments and synths is great. That main violin melody is so catchy- I can definitely see the Mario Galaxy influence! Composition wise, the sections flow into each other really nicely and it creates that feeling of floating underwater. Only nitpick I have is that you could include more low end instruments as at the moment it sounds a bit thin without the weightiness of a bass- but of course that's all down to stylistic choice. Overall really good job :)