I like the song. You have a really interesting voice. I tend to draw comparisons to other artists, so hopefully this is not offensive, but I hear a Bowie vibe to it.
Another section that would deviate from the chord pattern would be nice, but I suspect you are probably too invested with the song structure as it is now. It works as-is, but some variation would add to it. Of course you'd have to write a whole other section, and I know what a challenge that can be.
The background vocals will work. The problem I'm hearing with them now, is that they are not in very good time with the song arrangement. They come in too soon, or too late, but not on the correct beat within the measure. They do get better as the song progresses. 1:20 and 3:16 for example, is how they should sound more or less, everywhere. For the distorted guitar part at 2:26, I'd suggest using the same chords you do on the beginning, only up in 5th fret area. x5777x / x0758x or x0578x / C / G etc.
Cool song.
