This Seeking Tech guide will show you how to get the “To the Rescue: Metal Slug 6” trophy in the PS4 version of Metal Slug Anthology.
This will unlock when you “rescue at least 10 prisoners in one Metal Slug 6 mission.”
The easiest mission to do this is in the first one. Play cautiously so that you don’t get killed. If you do get killed, then you will lose all of your rescued prisoners.
You will be able to rescue up to 15 prisoners on the first mission although you only need 10 to unlock this trophy. You should find them easily on the main path as long as you don’t die.
When you encounter the boss, stay on the left edge of the screen to avoid most of his attacks. You should then only worry about the rock throws.
If you need a visual aide, then you can check out the following video walkthrough: