The musical arrangement/instrumentation needs work. First of all, there's a clash in the bass region at around 0:18. That clash repeats numerous times throughout the song. 2:20 has some other bass clash. It's important that the bass note be clearly and unambiguously stated as the overtones are generated off that note.
It sound like you currently have three different instruments playing in the bass region; piano, bass and organ. The piano/bass guitar unison can be an attractive sound, but I would suggest using that device sparingly. Let the bass instrument play the bass part and delete the MIDI notes from the other parts. It'll sound a lot cleaner.
Some rhythm guitar would be good for this song as well.
J