“Johnny Mnemonic” is loaded with practical effects — like a cybernetic assassin with a penchant for the Bible, gun play, and martial arts sequences — but the scene that has aged the most involves computer generated images. That is, perhaps, not unexpected: practical effects usually retain their potency, but CGI graphics often age rapidly due to the rate in which technology improves. The graphical power in computers surged enormously from 1995 to 2005 (via Tom’s Hardware), and the processing power of computers has increased at a geometric rate, known as Moore’s Law (via Investopedia). As a result, CGI that holds up over time is rarer than CGI that looks dated a few decades later.
In the scene that looks the fakest today, though, Johnny is forced to hack his own brain, which involves him being strapped into a virtual reality headset and aided by a psychic dolphin, trained by the military, known as Jones. This faux-reality sees a barely recognizable avatar of Johnny navigate the storage space in his own mind, and when he comes up against the innate defenses of the data in question, Johnny’s digital character creates a clone of himself while also growing talon=like appendages from his hands, which he uses to physically hack away at the defenses.
At the time, it was a dazzling display of fancy computer graphics, but these days, the images look rather pedestrian, at best. The truth is that our smart phones today have significantly more power than even the beefiest computers of the mid-1990s, so the graphics look just a wee bit dated. Still, it would have been impossible to film the hacking scenes with practical effects, and they now act as a quaint time capsule for computer graphics of the time.