|Gamespot has written a review of .hack/infection for PS2, and they came to the conclusion that this game is good, but not oustanding. Their rating: 7/10. Here's a bit:
You can finish the game in 20 hours or less, though you can continue playing after that, unlocking some secrets and finding better equipment. Subsequent installments in the series will optionally allow you to export your character data, continuing on from where you left off. And hopefully future installments won't merely offer more of the same random hack-and-slash gameplay along with another 15-20 hours' worth of story that doesn't go anywhere. It's not that the first game in the series isn't any good--it's just that the concept is much better.