Hey friend.

I recently found some MGS2 Substance codes at codemasters-project.net that work perfectly. These codes worked in all modes and all characters.

No Reload
001932DC 0000001E

Invincible (Press L3 to turn ON, R3 to turn OFF)
D01EAD02 0000FFFD
001F1946 0000008B
D01EAD02 0000FFFB
001F1946 00000000