Although Killer is Dead is neither a follow-up to Killer-7 nor the No More Heroes series by the same developers, it does have certain similarities, including violent action, the main character who primarily uses a katana as a weapon, assassins as a significant motif, and a cel-shaded visual aesthetic. The killer is Dead is broken up into 12 episodes set in various parts of the globe and features Mondo Zap as its lead character. He works at the Bryan Execution Firm as a contract executor. In the Game's futuristic setting, Monda is hired to kill cyborgs and assassins.

A summary of the operation's goal is presented against a global map before each mission, and frequently animated scenes further the plot between the action. A primary mission's completion typically unlocks several side tasks.

Plot

When Tokio's replacement kills the deranged former assassin-turned-kidnapper, his darkness rises to the Moon in the Game's opening scene. Mondo sees his predecessor died at Bryan's hands two years later. Then, Mondo is dispatched on missions against those who have been affected by Malice, which turns them into monsters and forces them to commit wicked things. Moon River, the Moon's ruler, assigns David one of his first missions: to kill him after he usurps her. Mondo and David engage in combat, but Mondo cannot kill him. David subtly suggests that to become stronger, he must consume the blood of those affected by Dark Matter. Mondo agrees to let Moon River stay with him while she waits for the contract to be finished.

Mondo continues his campaign against Dark Matter-infected individuals. Each time a victim is killed, Mondo's arm absorbs a fragment of the target's Dark Matter and their blood, inflicting him with severe anguish. Dolly torments him in his nightmares, where he has visions of Moon River and a strange blue unicorn playing with him when they were kids, as well as David assaulting his home, killing his mother, and chopping off Mondo's arm before being dropped off at the Bryan Execution Firm by the unicorn. Vivienne contemplates killing Mondo during one mission when the Dark Matter engulfs him. On a different assignment, Mika, who is also under the control of Dolly, almost kills Bryan.

Mondo remembers the truth—he and David are brothers, and David was one of Bryan's former Executioners before becoming corrupted with Dark Matter—during his final struggle with Dolly to free himself and Mika from her hold. Bryan then prepared Mondo to defeat David. To find out who would be David's designated killer, David, in turn, installed Mika, the girl Tokio kidnapped, and David freed as a spy. David also plans to install Mondo as the Moon's new ruler while he conquers Earth. Mondo and David square off in decisive combat on the Moon, with Mondo employing the strength of Dark Matter to prevail. As a result of consuming David's blood, Mondo loses control and tries to stop the flow of Dark Matter by amputating his robotic arm. Moon River issues a new contract for Mondo's life, and Mondo succeeds David as the ruler of the Moon and its Dark Matter.

SUDA51, a renowned designer, is about to unleash some seriously stunning action. Players will chop, dice, and shoot as the slick executioner Mondo Zappa in this special PC edition. Get ready for KILLER IS DEAD's thrill of the kill!

Features unique to the Nightmare Edition:

• A brand-new Level of difficulty dubbed Nightmare Mode. Adrenaline Burst, Dodge Burst, and Headshots are the only attacks that may be used to beat foes in this mode, making the gameplay much more tactical and skill-intensive. The Final Judgement finisher (QTE mode) won't be available for usage by players to defeat foes.
  
• Theater Mode: After your initial playthrough, you can review sequences and learn more about the characters' backstories. This can help you figure out the plot.
  
• There will also be a Smooth Operator Pack for the console, with X-ray glasses, glamorous attire, gorgeous women, and a lethal new Quest and boss!