The complete box also includes a Digital Copy and a Supplementary disc crammed full of extras, such as an interview with star, Yuuki Kudou.
Here's a taste of it. You can seek it out on the interwebs by yourself.
Interestingly enough, it also contained a complete script in English (appropriate, since it was filmed in English.)
There was a live action version way back in 2009 and I wrote about it here.
Now all I have to do is locate the 51 follow-up anime episodes and I'll be all caught up.