Wall in G Major

I wanted to experiment with just using one chord, to see if I can create an emotional impact. It somewhat worked, but I added another layer of harmony towards the end. Let me know what you think! 

Nice stuff. After so much of the same, it feels extremely significant when that F# is introduced over the drone. However, I feel like it very strongly wants to shift to the IV chord to get a resolution from F# to E. Subverting expectations isn't a bad thing, but I feel that so strongly that resolving back to the G major drone sort of feels like a lot of build up for nothing to me. That's just my subjective experience of the music though.

If this is the sort of think you'd like to study, the prelude to Wagner's Das Rheingold is roughly 5 minutes made up entirely of an Eb Major chord, and it's probably the best example of how to write something effective with a single chord.

This is where you have to realize music doesn't really mean anything in itself. When boiled down, this piece is a series of G major (+7+9) inversions. Written in score form, that's all I would see, and honestly, the sound of the music doesn't matter at that point. @fishyfry notes a tendency for tones to shift, and that's because in your exercise to create a piece with one chord, you forgot the music.