Shadow Master (PSX)

Cheat Codes:
Start a game, kill the first two aliens and enter the room from which they came from. Then, enter one of the following codes:

All weapons with infinite ammunition:
Hold L1+ L2 + R1 + R2 + Circle. If you entered the code correctly, you will see a red light.

Invincibility:
Hold L1+ L2 + R1 + R2 + X. If you entered the code correctly, you will see a blue light.

Level select:
Hold L1+ L2 + R1 + R2 + Triangle and then quit your current game. If you entered the code correctly, you will see a green light. Now go to the the opening screen and you can choose a starting level from 1 to 16.