Creator Backlash: The Miller brothers have expressed their regrets for the underground mazerunner puzzle in the Selenitic Age, saying they didn't expect anybody to actually map that puzzle out (The idea was for you to listen to the sounds and use Trial-and-Error Gameplay to figure out which cardinal direction the sounds meant, but very few people got the hint).
Killer App: Originally, it was one of the selling points of the Mac. And when it was finally ported to the PC, PC owners actually bought a sound card and a CD-ROM drive along with the game (the latter was necessary as the game only came on CD-ROM, the former was necessary to enjoy the game fully since a typical PC of the era had no built in sampled audio capabilities- also, sound cards of the era included a built in SCSI controller, which is actually necessary for adding a CD-ROM drive to a PC because IDE CD-ROM drives weren't developed yet and all CD-ROM drives of the era only had SCSI interfaces). In other words, it was the killer app that nudged the PC towards the built in audio and multimedia path that it is following today.
And Dilandau3000 did Let's Plays of the other games of the series, later asked by popular demand to do the same games shady did. He even did URU Live with a friend.
Port Overdosed: Perhaps the most widely-ported graphical adventure game in history.
Real-Life Relative: In the first game, the brothers Sirrus and Achenar are played by real life brothers Rand and Robyn Miller. Rand also played (voiced, in End of Ages) their father, Atrus, in all games.