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.

Killer 8 - 100 Serum Vials:
Press Down, R1, Up, L1, Square, X, Triangle, Triangle at the the "Press Start" screen. You will get the vials when you start Target: Angel. Repeat the level over with the code enabled to get another 100 vials.