A bit lacking
I'll first say, it's a very good start, but if I were to analyze the entire song it seems it is nothing but a series of different lead lines/melodies, some with a drum track, others without. So basically, minus the drums, on a keyboard the song could be played with just one hand.
You are looking for ways to improve, and keep in mind this is only my opinion, but I think the song could use at the least, bass lines and also I think adding some backing chords couldn't hurt. Nothing loud or too noticable, but I think it could go a long way.
I also can't help but ask what program you used. I'm not really a big fan of the retro sounds, but it all depends on what you were going for.