The world has finally embraced global peace. A network of intercontinental expressways has been established, bridging the continents. Radioactive materials and weapons of mass destruction have been eliminated, removing all threats to peace. Then in a major turn of events, the world stood in silence as a new fear was unleashed and the 'killer 7' was commissioned to handle this new threat to mankind.

In killer 7, players take on the role of Harman Smith an unlikely assassin who leads a life as the "master" who rules over seven alter egos. Switching between his seven different personalities, Harman employs each personality's unique abilities to complete their mission. Now, a powerful underworld kingpin has unleashed violent creatures onto the world called 'Heaven's Smile.' These crazed soldiers, affixed with horrific smiles, have started to wreak havoc on city streets. It is up to the player to interchange Harman's seven 'partners' and utilize the special powers that dwell within them in order to assassinate Kun Lan, the notorious criminal overlord behind all the madness.

A 12-part comic book series based on Killer7 is currently being published, according to Wikipedia. As of 2 March, 2007 issues 1-4 have been released. They are published by Devil's Due Publishing and re-tell the events of the game with added dialogue and scenes to better convey Suda 51's original concepts and to make them easier to understand. So far it has received mixed reactions.

The codes and unlockables below are guaranteed to make gameplay a piece of cake:

Codes

Killer 8 - 100 Serum Vials:
Press Down, R1, Up, L1, Square, Triangle, Circle(2), at the the "Press Start" screen. The healing sound will confirm correct code entry. You will get the vials when you start Target 00. Repeat the level over with the code enabled to get another 100 vials.

Unlockables

Killer 8 mode:
Successfully complete the game under the normal or hard difficulty setting. Young Harman is a playable character in this mode.

Hopper 7 mode:
Successfully complete the game in Killer 8 mode.

Alternate ending sequence:
Successfully complete Killer 8 mode.

Here's some gameplay footage: