Killer 7 Cheats

Killer 8: 100 Serum Vials
Press [Down], [R1], [Up], [L1], [Square], [X], [Triangle]x2, at the the "Press Start" screen. The healing sound will confirm correct code entry. 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
Successfully complete the game under the normal or hard difficulty setting.

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

Play as Young Harman
Successfully complete the game under the normal or hard difficulty setting.

Thick Blood & Serum
Thick blood is not carried over from stage to stage, but serum is. The blood machine in each stage will cease to function if you revisit the stage, so learn to collect as much thick blood as possible in a stage and break the machine before moving on.