Killer7 Cheats

Killer 8: 100 Serum Vials:
Press Down, R1, Up, L1, Square, X, Triangle(2), at the the "Press Start" screen. You will hear the healing sound if you have entered the code correctly. You will get the vials when you start Target: Angel. Repeat the level over with the code enabled to get another 100 vials.

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

Hopper 7 mode:
After finishing the game in Killer 8 mode.

Alternate ending sequence:
After finishing the Killer 8 mode.

Killer7 Official Website

Killer7 Review - Silicon ERA

Killer7 Review - GameSpot