This Seeking Tech guide will show you how to get the Falling for Crates trophy and achievement in Metal Slug XX.
To unlock this, you need to “trigger the 100 Morden Soldiers encounter in Mission 2.”
Use the following video as a reference:
For the first step, head to the start of Stage 2.
When heading down the fight elevator, go right and then avoid attacking any of the Morden Soldiers. Instead, break the crate to the left without harming the soldier next to it.
You then need to break the crate that should appear next to the soldier on the siren.
If done correctly, the trophy should unlock.