| Effect | Code (Enter at title screen) | |--------|------------------------------| | (Metal Slug 1, 2, X, 3, 4, 5) | ↑ ↑ ↓ ↓ ← → ← → ↑ ↑ ↓ ↓ ← → ← → (then hold ╳ + ○ and press START) | | Arcade mode level select | Hold □ + L + R, then enter ↑ ↓ ← → ↑ ↓ ← → (varies by game) | | Enemy change / color edit (Metal Slug 6 only) | At title, hold L + R, then ↑ ↑ ↓ ↓ ← → ← → ↑ ↑ ↓ ↓ ← → ← →, release L+R, press START | | Infinite grenades | Some games support ↓ ↘ → ↑ ↖ ← + ╳ during gameplay (finicky on PSP) |
To unlock the game's secret gallery content, you must complete the games under specific conditions Metal Slug Anthology Psp Cheats