Unlock Karen card:
Enter KAREN as a password to get a card featuring Karen from Policenauts.
Unlock Mika card:
Enter MIKA as a password to get a card featuring Mika from Snatcher.
Unlock Viper card:
Enter VIPER as a password to get a card featuring Black Arts Viper from the Metal Gear Solid on the Game Boy Color.
Unlock XM8 card:
Enter XMEIGHT as a password to get a weapon card with 50 attack, 60% hit, 5.56mm bullets, 6 shots, 70% reaction, move 6 spaces, knockback, and burn.
Unlock Jehuty card:
Enter JEHUTY as a password to get a card featuring Jehuty from Zone Of The Enders. This card will destroy all equipment and equipment level-ups in the current room.
Unlock Bikini model clip:
Enter SABRAGE, NOMEL, ELYTS or MAEB as a password to see clips featuring Japanese bikini models. Note: These will cause Snake to get a nosebleed, but has no effect on Teliko.