Just out of curiosity where some one was having problems with shadow detail I used GIMP levels on the shot.
Initial
Result
The settings used
The histogram was bunched up. The left and right input pointer have stretched the output to full white and full black. The middle slider adjusted for the contrast in the lower mid tone range. The output pointers can be used to set where the output will be. In this case full black and full white. It can be helpful in many way. Auto for instance can clean up colour balances or at least indicate which channel is out. It can also be used in much the same way as curves can but is far less delicate to use.