Pretty cool. Nice retro feel, and I love the vocal. Like the lead guitar too.
A few ideas for mixing:
Compress the vocals to even out the level a wee bit. Be careful that you don't make the vocal too dull by doing this.
Maybe take a bit of low-end off the toms - they might be a little less over-bearing that way.
Bring the snare to dead-centre - it sounds really weird over on the left.
The distorted chords *definitely* sound like they're mixed to the centre.
If you only have one rhythm guitar track, simply copying it and panning one left and one right will NOT give a double-tracked effect. If you do this, it'll just sound like it's mixed to the centre.
If you can't get a separate rhythm track recorded, you can do a couple of things:
1. Delay one of the tracks very slightly - this can help "separate" two identical tracks.
2. EQ the two tracks slightly differently - this also helps give a better double-tracked feel.
Ideally you want to do what Kramer sugegsted - record a second rhythm guitar track, and use the original track on one side, the new track on the other. Even in this situation, using slightly different EQ on each can help separate two very similar rhythm tracks.
I'm a sloppy enough player that two runs through the same track don't even sound slightly similar!
Hope this helps
Alastair