Quick reply, haven't listened to the update:
Having effects doesn't mean using effects right. You have a very exposed sound. Some genres and styles can do this, and chiptune-y stuff generally doesn't need a lot of effects. But tracks still need their own place in the mix. Start with the levels, then push tracks into their own frequency ranges and give them the sense of space (with reverb) that they need. That's the order I recommend doing it in. Dunno how much you've already done.
What I call expression is the feeling that there's an emotion behind the sound. A static waveform, which many simple synth patches have, generally doesn't have a lot of emotion. While that's fine for fast melodies where the expression comes from other things, slower melodies end up sounding robotic when the simple sound designed is exposed. That's when you want small things changing in the sound. A good analogy is the violin, because a violinist will vary the vibrato and the strength of the stroke all the time, and sometimes lag behind the beat slightly, or do other things based on what they feel the melody needs. Timaeus covered some of the tools and techniques to use for this.
The tracker scene is about using old tools (trackers) to make music. A lot of chiptunes are made in trackers, but there are non-chip-based trackers as well. A lot of old game music was made in trackers. It's got its own sound because the tools lent themselves to certain techniques. I like that sound. It's part of what got me into music.
Minor sources don't need to be sourced if the main source is dominant. If you want to mention them, that's fine.
The overall impression I got was a good middle, a weak beginning and end, writing-wise. The sound was raw and exposed, and had some track level balance problems. Dunno how the new version sounds. Hopefully better.