YES!!
In my opinion, Infection is the hardest .hack game. Granted, I was in like, 3/4th grade when I played it, but STILL! It took me three years to beat the first game, and a fourth year was used up with all the others.
Each G.U. game took me less then a month.
The Net Slum [a guild for .hack fans]
A guild for fans of the anime/game series, dot hack.