METAL SLUG ANTHOLOGY

In order to "rescue" a prisoner in a level, you must free them from their captivity AND finish the level without dying after getting them or else they become recaptured and you lose them from your count towards your end total. You can still get the trophy if you lose prisoners during your level playthrough as long as you have 10 by the time you finish the level.

The first level is probably the easiest to get this trophy as the level itself isn't that difficult to complete without dying. The location of the missions prisoners are as follows:
 

(Note: The video shows the locations of all the prisoners throughout the level even if I don't have them all still saved by the end)

• 1: Near the beginning on the mission on a boat plateau
• 2: On top of a large boat
• 3: On the upper level after blowing up the large boat
• 4: In front of you as you enter the swamp area
• 5: On the boat along your path
• 6 & 7: Tied up above you while riding on the boat
• 8 & 9: Just past the last 2 prisoners also tied up above
• 10: Again, right after the previous ones tied up above
• 11: You guessed it, right after those tied up above
• 12: Drops down on to the wooden walkway during the boss fight