The Lawnmower Man game is based on the 1992 movie of the same name, which was loosely inspired by a Stephen King short story. The game follows Dr. Lawrence Angelo, a scientist working for Virtual Space Industries in "Project 5", as he tries to increase the intelligence of primates using psychotropic drugs and VR training. After one of the chimps escapes and shoots a guard, Angelo is forced into a vacation, where he meets Jobe Smith, a simpleton who becomes the first human subject in the experiment.
As the experiments progress, Jobe's intelligence increases dramatically, but also develops violent tendencies after being subjected to the psychotropic drugs. The player must control either Dr. Angelo or Carla Parkette as they try to stop Jobe from taking revenge on those who abused him and plotting to take over all computers in the world.
The gameplay is a side-scrolling platformer, where the player can collect better weapons or data discs to gain advantages. The game features four different virtual worlds, each with unique obstacles and challenges. These levels are based on the true-3D level connectors of the movie's CGI sequences, requiring the player to avoid obstacles and enemies at high speed.