The mix is very midrangey. Could be youtube has crapified your original mix.
Switch YouTube to at least 720p to get a less-compressed audio.
It's still got a very squashed and boosted mid-range, but there's a little more sparkle on it.
I also recommend attaching or linking the direct mp3 rather than a YT video, bainmack. Youtube applies compression that interferes with our ability to really hear what you did, and using the hassle of exporting and uploading a new video tells us you're probably not going to do any revisions of the song. (Thus, why should we bother helping you improve it?)
Yeah, there is something very squashed about the mix on the Youtube link. But I also hear some vocal 'ess's that tell me the mix has some issues previous to Youtube compression. The cymbals should have that high end air that the main vocals have. Agreed the backups sound dark. Also I hear a disturbing slap on the kick around 600Hz that could be cut a bit.
And at the halfway point in the song it seems to get boomy around 220 Hz. Thinking bass guitar or maybe the kick is fighting your master limiter.
And after all that bitching, really cool tune man! I dig it!