The Lawnmower Man

In the book, an unassuming everyman stumbles upon the fact that a local landscaping company is actually a front for a demon who has an arrangement that involves making human sacrifices of those that discover his supernatural nature.

In the movie, a Cyber Virtual Reality 3D Battles ON 3D CYBERSPACE Stunning Effects 3D Internet Pierce Brosnan Warfare Nineties Futuristic VR Headset Technology BATTLE In 3D Mind Expanding Guns, and one of the characters is a man who has a lawnmower.

Edit: Shit, okay, I just read this on Wikipedia and nearly wet myself:

A feature film, The Lawnmower Man, starring Jeff Fahey and Pierce Brosnan, was released in 1992 by New Line Cinema. This film used an original screenplay entitled “CyberGod”, borrowing only the title of the short story. The film concerns a scientist, Dr. Lawrence Angelo (Brosnan), who subjects mentally challenged Jobe Smith (Fahey) to virtual reality experiments which give him superhuman abilities. The film was originally titled Stephen King’s The Lawnmower Man. King won a lawsuit to have his name removed from the film, stating in court documents that the film “bore no meaningful resemblance” to his story. King then won further damages in 1993 after his name was included in the home video release.