The song has two components, piano & synth.
For piano, the sound quality is good + your Melody is absolutely nice.
The synth plays simple note in the back, but here is what I think,
The sound of piano and the sound of synth are not completely matching. (And here I do not mean the notes it plays, but rather the sound itself)
The synth is more relevant with sounds coming from somewhere far. Just try to add reverb to the piano and you will know what I mean. (Along with faint delay and feedback with proper timing)
Also you can spread the synth sound more by using some effects like "Flanger".
You have the option also to replace the synth with strings and play more complex chords rather than simple single notes. It will definitely add dimension and feeling.
Cheers
