Bonus Cards in Metal Gear Acid:
In the main menu, select Password and enter the following passwords:

Viper - Gives Card No.173 - Viper
Mika - Gives Card No.178 - Mika Slayton
Karen - Gives Card No.182 - Karen Houjou
Jehuty - Gives Card No.184 - Jehuty
Xmeight - Gives Card No.199 - XM8
Sabrage - Gives Card No.200 - Kosaka Yuka (Japanese version only)
Nomel - Gives Card No.201 - Yoshida Asaki (Japanese version only)
Elyts - Gives Card No.202 - Saitou Yuu (Japanese version only)
Maeb - Gives Card No.203 - Shibuya Eri (Japanese version only)
Umeda - Gives Card No.201 - Asaki Yoshida (US Version)
Kobe - Gives Card No.200 - Kosaka Yuka ( US version only)
Roppongi - Gives Card No.203 - Shibuya Eri (US version only)
YEBISU - Gives Card No. 202 Yu Saito (US version only)

Unlockable Cards:
Solid Snake (MG) Card - Finish the Game Once.
Raiden Card - Finish the Game twice on any difficulty.

MGS3 Connectivity:
(Japanese/European Version only) If you own the Japanese/European version of AC!D and the Japanese/European version of MGS3 , connect your PSP to your PS2 using the link cable and put the PSP on the "USB connection" option. Then start or load a MGS3 game and you will have recieved the Stealth Camo and the EZ gun. You can then save your game and keep the items even after your PSP is disconnected. This does not work on the US version.