With a little bit of mixing, this could be an awesome lo-fi chill song!
The piano part is catchy and works nicely with those drums! I love that you kind of lay the ground work with the piano in the first half, and then spice it up in the second half. It expands the tone of the piece with extra flavor, but stays faithful to the original melody. In terms of arrangement, I think it needs a little bit more instrumentation. A bass would really help round out the whole song and make it feel a bit more complete. You could also throw in some strings that lightly play long chords in the back just to fill in some of that sonic space.
The mix is clean but quiet. You could certainly bring up the overall volume of the piece while maintaining that quiet feeling. If you were to add more instruments, it would take some intentional mixing moves to make sure they all play nicely with each other in the sonic spectrum. Still, you did a good job keeping the dynamics of the song well balanced. (loud parts and soft parts are clear, but not overly contrasted)
Overall, I think you've got a cool little tune! I think it needs more instruments, (just one or two) but that is just my personal preference. Great job! Keep it up! :)