Did you burn in the back of the tunnel a little? It looks a little darker than the light on the front of the tunnel (but it may not be). I would like to see what the image would look like with the back of the tunnel a little brighter...I think it would give a greater feeling of depth and give one's eye a third element to bounce aound on (Margot, the back of the tunnel and the light area in the lower left of the image.)
I didn't do anything except a slight crop on the left side. Every shot I make is tilted about one degree. I like the suggestion to lighten the back of the tunnel. I'll have to remember that, thanks.