Nicely done.. But there seems to be too much empty space for my liking. Don't take that in an offensive way ^_^' Since my first wall had a lot of empty space in it as well -_- But I do really like the brush work, it gave off that nice grundge feeling :D :D I really like.
As for the empty space thing, it would kinda help if you made the wallpaper in a smaller resolution. But don't make the whole thing smaller, just the size of space your using for you wall. In other words, the scan you used and brushes are still going to be the same size, but in a smaller area ^^ Hope that made some sense .. I don't think I'm that good in explaining things ^_^'
The compostion of this wall is great as well :) You've improved since your last wall. Keep up the good work! :D