The song fit the background theme so nicely. Some tips I might add to improve would be to adjust the velocity of the notes of the piano, as it sounds a little too synthetically played. For example, I first might increase velocity more on the first beat, then adjust the next few beats, and then either decrease the last note on the measure, or increase it; depends on where we are in the song.
Also, while I do appreciate the different chord changes throughout the song (0:48, 1:20, 2:08, 2:40, 2:58), it can sound a little too abrupt for the listener. I would work on smoothing out these transitions.
You have potential, certainly, so keep working and producing music!