- Defictionalization: .hack//Fragment is an online multiplayer game, essentially bringing The World to the real world.
- There's also several fan games that attempt to recreate, or pay homage to, the World. The results are with limited success for one reason or another
- Dueling Games: Square Enix attempted to sponge off the series' success with an Action RPG named Code Age Commanders, which would have been followed up with a anime and manga series, as well as portable spinoffs. However, the mothership game failed and sunk any chance of having a series developed around it.
- Hilarious in Hindsight: The main setting, The World, is a VR MMO played by wearing a headset, and using a controller, and has surprisingly lifelike in-game character movement. VRChat is a real life VR MMO that's best played wearing a headset, can be played with a controller, and can have surprisingly lifelike in-game character movement (especially if you get a Full-Body Tracking setup made).
- No Export for You: .hack//frägment an online RPG version (not to be confused with an MMO) that allows custom created characters on a playable online server. Also .hack//Link, .hack//Versus.... Pretty much anything released after the GU Saga wrapped up never got released outside Japan aside from a couple of OVAs.
- The Other Darrin: Balmung was voiced by Doug Erholtz in the first game of the original tetralogy. He is voiced by Crispin Freeman from Mutation onwards. This is in cutscenes only, however; Erholtz' voice is still used for battle vocals. Evidently they recorded them before Erholtz was replaced.
- The Wiki Rule: The .hack//Wiki.
Trivia / .hack