Unlike later compilations, the PSP version of Metal Slug Anthology does have a traditional "enter code at the title screen" system for the main arcade modes. However, you can unlock special features (art galleries, sound tests, and Caravan Mode —a timed high-score challenge) by completing specific in-game tasks.
Play Metal Slug 3 or 5 on Hard mode. When you defeat the final boss, save the game immediately as they explode. Let the credits roll to receive your 5 tokens, then exit to the main menu. Reload that same save to instantly trigger the ending again, earning another 5 tokens each time you repeat the process. 3. CWCheats for PSP/PPSSPP
You can unlock galleries and music by completing the games under specific conditions. Most of these require you to beat the games with . Unlockable Requirement Art Gallery 1–7
If you are playing on an emulator, you can use "CWCheat" codes to force effects like infinite lives or invincibility. You must have the ULUS-10154.ini (North America) or ELES-54442.ini (Europe) file in your emulator's cheat folder. Common Effect Cheat Engine Address (Example) Metal Slug 2 Infinite Arms [P1] _L 0x0114366C 0x000003E7 Metal Slug 2 Infinite Bombs [P1] _L 0x01143669 0x00000063 Metal Slug 2 Invincible [P1] _L 0x01138836 0x00000064 Infinite Lives Varies per title in the anthology