The messenger pigeons used throughout the game are are all named after Bond Girls from the James Bond series. Not only this, but Emir Parkreiner's gun is the namesake Golden Gun from the Jame Bond film The Man with the Golden Gun.

The game was allegedly delayed in America so that it would be released on July 7th (7/7). However, it ended up being released two days earlier on July 5th.

In 2006, Devil's Due Publishing began releasing a 12-issue limited series comic book adaptation of Killer7 that was written and drawn by the independent company Kinetic Underground. The plot of the comic was somewhat streamlined from the plot of the game, but the writers deliberately did not spoonfeed information to readers in an effort to still stay true to the game. However, due to low sales, the comic was cancelled after six issues, four of those being properly numbered Issues #1-4, as well as a promotional Issue #0 that was released as a bonus with copies of Killer7 pre-ordered from EB Games, and a promotional Issue #½ that was only released at San Diego Comic Con 2005.