Killer 7 - Platform: Playstation 1

Hopper 7 mode:
--------------
Successfully complete the game on the Killer 8 difficulty setting to 
unlock the Hopper 7 difficulty setting.

Killer 8 mode:
--------------
Successfully complete the game on the normal or hard difficulty setting 
to unlock the Killer 8 difficulty setting.

Play as Young Harman:
---------------------
Successfully complete the game on the normal or hard difficulty setting 
to unlock Young Harman.

Thick Blood and 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.