Hey, good job! I loved some parts and samples of the song!

What I would suggest is this:
Refine the sine Synth you are using, maybe using a reverb or something to make it just a bit less thin,
For the piano keys near the begining, I love the idea, but to make it sound more real, try using a Sidechain, or again, dont keep the notes at the same velocity!

Keep up the great work bro!