In the original review, I mostly talked about the movie version of this story. To give the manga a fair shake, it's well written and drawn, but it's still slow-paced (even for a manga) and our hero's revenge still depends entirely on those he is pursuing. He hasn't become proactive, yet.
Goto, our hero, pursues his revenge with great deliberation, and it's only when the enemy reaches out to contact him that things start happening. The artist also spends a great deal of time -- too much, actually -- establishing the mood and the surroundings and how many cigarettes everyone is smoking. I think I'll stick with the movie, mean-spirited as it was.
OldBoy vol. 2 and vol. 3 are both available from Right Stuf, Intl., an online retailer specializing in anime and manga.