So the song starts in a very chiptune style, chiptune is hard for me to judge because im not sure what kind of mixing problem one would run into. I'm sure its a lot harder than i think it is.
For instance, man you are making some SPICY TASTY chords but they are conflicted in the frequency spectrum. Your sub is great, but the "Bass" arpeggiated voice is SO close to the chords. so the chords get drowned by the rythm synth or "bass" like ADR3 said, and i have to really listen for those spicy tasty chords instead of just hearing them. i think that bass or rhythm synth wouldve sounded fine an octave down, or turned down a lot, or simplified when the chords come in.
Now im confused why you went from chiptune to piano, and the piano is pretty loud and over compressed, the violins once again are drowned by this rhythm you have going on with arpeggiated piano, i love the little arpegiated high notes you add in at 1:36.
this song got really overshadowed by that over balanced bass line or rhythm synth.
your transitions are a bit lacking overall, simply just going to a new idea instead of adding a transitional section. transition in my opinion and widely accepted in the industry, are HUGE. and can make or break your song. Yours arent TERRIBLE or song breaking, just more or less not really there.
Overall, ADR3 said it all very well, I can't add much more, great submission and Good luck!!