Considering the normal edition retails for 30 at some places (and 20 at others, I'm aware), this is a pretty good deal. Especially if you like action figures (although my Big Daddy's drill was chipped when it arrived - didn't order from Game though) and other such tie-in shenanigans.
You can also get some quidco on this, so don't forget that!
Bonus DVD with "Making Of..." Videos
Big Daddy Figurine