Despite its title and similar theme, developer Grasshopper Manufacture made clear that Killer is Dead is not a sequel to Suda 51's GameCube/PlayStation 2 game Killer 7. The game launched in Summer 2013 across the globe, with XSEED publishing in North America and Deep Silver publishing in PAL territories.
The story begins in a darkened alleyway where a kidnapper named Tokio with a mechanical gun-arm tries to escape while a silhouetted Executioner with a sword simply bats away all of his shots and slowly walks forward. The kidnapper manages to get the drop on the Executioner and shoots him dead, but the Executioner simply gets back up and cuts off his gun-arm before killing him.
The game the switches to the present with Mondo Zappa, who has officially become a State-sanctioned Executioner--an agent who travels the world in order to take out "S-Level Criminals"--for the Bryan Execution Agency. Upon receiving confirmation that he has been employed by Bryan's office (but not Mika), he quickly receives his first job from an artist named Robert to slay a monster that has been terrorizing his neighborhood.
The job leads him to a weird house where he meets a girl named Alissa, begging Mondo to stop Alice after she was tricked by a "scary-looking man." After fighting his way through various rooms, he quickly discovers that Alice and Alissa were the same girl. She mentions that the scary man was named David shortly before turning into a hideous monster. Mondo slays Alice and ends up putting Robert's soul to rest.
Two weeks later, Mondo is sent on his next job, to kill his predecessor Damon. Before he dies, Damon tells Mondo that he needs to find a beacon of light that will never succumb to the darkness.
Later, the Agency's next contract comes from Moon River, the deposed ruler of the Moon. Mondo fights his way through a mansion on the Moon and comes face-to-face with David. He manages to slice his neck, but David simply retreats, telling Mondo he needs more blood to kill him.
The gameplay of Killer is Dead incorporates a mix of third-person hack-and-slash and third-person shooting mechanics. Mondo wields a katana named "Gekkou" which he carries with him throughout the game. Though the weapon cannot be changed, it can be upgraded with moon crystals. Mondo's left arm, "Musselback," can be used in melee to break the guards of enemies or transform into a type of gun.
A big part of combat is the dodge command. With one button, Mondo can guard against or dodge nearly any attack. A successful dodge allows him to enter rage mode, which lets him cut the attacking enemy several times over in a second.
Every successful melee attack builds up a combo meter that can be added to as long as Mondo is not hit or takes too long between strikes. With a high enough combo meter, the player will be able to perform one of four execution moves to gain extra health, blood or moon crystals while killing an enemy in melee.
As Mondo travels around the world, working his way through the story missions, various side missions will pop-up that can be completed in any order. Several of them include fighting through various Wires to retrieve an item for the Agency. A few involve taking command of a turret to shoot down waves of enemies. One involves lighting a series of torches to retrieve a cursed Japanese doll before Mondo's health runs out.
On top of those, there are the "Gigolo Missions" where Mondo must stare at a lady repeatedly to build up enough "Guts" to give her a present, then repeat the process until either the woman beds him or time runs out and she leaves. If Mondo gets caught staring at the woman's body too long, the target will get pissed off and leave him anyway.
Through successfully completing Gigolo Missions, Mondo can unlock extra sub-weapons for Musselback, including a drill, a freezing gun, and a charge cannon.
There are also "Scarlett Missions," which are unlocked as Mondo discovers various hiding places of Scarlett throughout the story. By completing Scarlett's challenges, Mondo can build up enough Guts to earn a chance to bed her.
Development of the game started in Spring 2011 while the planning originally started as far back as 2009. Yoshimi Yasuda is the executive producer of the game, with Suda 51 working as the executive director and scenario writer. Suda has stated that he was inspired by thinking of the dark side of the moon in conceiving the game's premise. More specifically, he has said that the game is a darker take on Ian Flemming's James Bond series, dubbing it a "Dark Side 007". He also cites "Hissatsu Shigotonin", a samurai drama show about hired killers, as a source of inspiration, and compared Mondo to Patrick Bateman from the film and novel American Psycho.