Level Password 

2 HBJNV94B2BWDP 
3 NNNXQWBDSVWBN 
4 WQSX4!VD!0CJB 
5 20X00646S8C3Z 
6 8!604?QJ!?CL5 
7 9?!1MWGKT?C1C 

View ending sequence  -  Enter "9?!1N?BKT?51G" as a password. 

Hidden sequence  -  Wait until the end of the credits to view the end of the story

Gameshark Codes

Infinite Cash   01ff7dc4  01ff7ec4
Infinite Health   018040c4
Infinite Glaive   0109B5CC
Infinite Scatter Gun   010950C8

Max Serum   010777C4
Max Armor   010778C4
Max Ammo   010779C4
Max Kung Fu   01077AC4
Max Sword   01077BC4