If you prefer "quality" gameplay without external cheats, use these built-in methods to unlock extras: Easy Token Farming: Play through Metal Slug 3
If you're looking to recreate Marco's run, here are the most stable codes for the ULUS-10216.ini file: metal slug anthology ppsspp cheat list extra quality
These can be entered directly on the screen without any external files: If you prefer "quality" gameplay without external cheats,