Okay, I know this is a little necromantic and reviving a long-dead thread about an old program is not always a good idea, but I just had to add my uninformed opinion
I watched it through on
Gooddrama.net where they have each episode (1-11) subbed, including the "Special" episode, which is like a "making of". They have split each epsiode into three 15 minute clips and include the commercial break captions (but not the commercials). It is very easy to watch on there and there are several encodings to choose from. They made the mistake of illustrating the TV drama series with a picture from the movie version, but the cast is correctly identified.
From the Special episode we can see that all filming was done on location and took about three months. For much of that it seems to have been extremely cold and many of the days were ridiculous long hours (Episode 7 had a shoot that finished at 31.00 hours, which is 7am in my language).
Also in that Special episode we can see some rather harsh words from the director towards Hatsune Matsushima and Yuka Kosaka. He came across as mean. I wondered if he was playing mind games; treating them badly on purpose to help the @DEEP actors form a bond between themselves. I can see how that might work. Of course, they were both "just photo idols" rather than actors, so maybe they were useless, I don't know. I liked them both.