.hack//G.U. Vol. 2: Reminisce is the second game in the .hack//G.U. trilogy and picks up where Volume 1 left off. The story takes place in "The World", a fictional massively multiplayer online role-playing game. You control Haseo, a player-killer killer whom along with his friends discovers they are unable to log out of The World. As is typical in the .hack series, there's a connection between events in the real world and in the online world and as the story continues Haseo will need to figure out how to save himself and his friends in both worlds. The story is told through a series of cut-scenes as well as by talking with other characters, receiving e-mails, and by finding posts in The World's online message boards. Since the game is a continuation of the previous game, many of the same locations and dungeons are utilized again.

The game uses a similar battle system as the previous game; a battle is initiated by running into an enemy that's visible on screen where you will then be able to perform a variety of attacks on the enemies in real time. Once again you can perform special Rengeki moves after performing a series of combo attacks which inflict additional damage. Also available are several awakening attacks which are the most powerful. During a battle you may have up to three members in your party fighting, though you only control Haseo while the other two characters are computer controlled. Experience points are earned for a successful battle which help your characters level up and become more powerful; a variety of missions, side quests, and dungeons are available allowing for numerous monsters of varying levels to fight.