Critical response
On the review aggregator website Rotten Tomatoes, 19% of 42 critics' reviews are positive. The website's consensus reads: "As narratively misguided as it is woefully miscast, Johnny Mnemonic brings the '90s cyberpunk thriller to inane new whoas -- er, lows." Metacritic, which uses a weighted average, assigned the film a score of 36 out of 100, based on 25 critics, indicating "generally unfavorable" reviews. Audiences polled by CinemaScore gave the film an average grade of "C+" on an A+ to F scale.
Variety's Todd McCarthy called the film "high-tech trash" and likened it to a video game. Roger Ebert, the film critic for the Chicago Sun-Times, gave the film two stars out of four and called it "one of the great goofy gestures of recent cinema". Owen Gleiberman of Entertainment Weekly rated it C− and called it "a slack and derivative future-shock thriller". Conversely, Mick LaSalle of the San Francisco Chronicle described it as "inescapably a very cool movie", and Marc Savlov wrote in The Austin Chronicle that the film works well for both Gibson fans and those unfamiliar with his work. Writing in The New York Times, Caryn James called the film "a disaster in every way" and said that despite Gibson's involvement, the film comes off as "a shabby imitation of Blade Runner and Total Recall".
McCarthy said that the film's premise is its "one bit of ingenuity", but the plot, which he called likely to disappoint Gibson's fans, is simply an excuse for "elaborate but undramatic and unexciting computer-graphics special effects". Ebert's review mirrored this view. Sending a courier to physically deliver important information while avoiding enemy agents struck him as "breathtakingly derivative" and illogical outside the artificiality of a film when the internet is available. In his review for the Los Angeles Times, Peter Rainer wrote that the film, when stripped of the cyberpunk atmosphere, is recycled from noir fiction, and LaSalle viewed it more positively as "a hard-boiled action story using technology as its backdrop". Savlov called it "an updated D.O.A.", and Ebert said the film's plot could have worked in any genre and been set in any time period.
James criticized the film's lack of tension, and Rainer called the film's tone too grim and lacking excitement. McCarthy criticized what he saw as a "unrelieved grimness" and "desultory, darkly staged action scenes". McCarthy felt the film's visual depiction of the future was unoriginal, and Gleiberman described the film as "Blade Runner with tackier sets". Savlov wrote that Longo's "attempts to out-Blade Runner Ridley Scott in the decaying cityscape department grow wearisome". Savlov still found the film "much better than expected". LaSalle felt the film "introduces a fantastic yet plausible vision of a computer-dominated age" and maintains a focus on humanity, in contrast to Rainer, who found the film's countercultural pose to be inauthentic and lacking humanity. James called the film murky and colorless; Rainer's review criticized similar issues, finding the film's lack of lighting and its grim set design to give everything an "undifferentiated dullness". McCarthy found the special effects to be "slick and accomplished but unimaginative", though Ebert enjoyed the special effects. Gleiberman highlighted the laser whip as his favorite special effect, though James found it unimpressive.
Although saying that Reeves is not a good actor, LaSalle said Reeves is still enjoyable to watch and makes for a compelling protagonist. McCarthy instead found Reeves' character to be unlikable and one-dimensional. James compared Reeves to a robot, and Gleiberman compared him to an action figure. Rainer posited that Reeves' character may seem so blank due to his memory loss. Savlov said that Reeves' wooden delivery gives the film unintentional humor, but Rainer found that the lack of humor throughout the film sapped all the acting performances of any enjoyment. Gleiberman said that Reeves' efforts to avoid Valleyspeak backfire, giving his character's lines "an intense, misplaced urgency", though he liked the unconventional casting of Lundgren as a psychopathic street preacher. Rainer highlighted Lundgren as the only mirthful actor and said his performance was the best in the film. James called Ice-T's role stereotypical and said he deserved better.
Jonathan Palmer reviewed Johnny Mnemonic for Arcane magazine, rating it a 4 out of 10 overall, and stated that "Though this is not a good film, the William Gibson connection alone makes it required cyberpunk viewing, and as the popularity of that genre increases, so will interest in Johnny Mnemonic."