Act III - Belly of the Beast
Downpour
COG Tag 19
Behind Building 3, which you open to access the elevator, head out to the far end of the dock platform over the sea to find the tag.
Evolution
COG Tag 20
In the area with floorboards that break beneath your feet, go immediately right then follow the platform to the far end to grab the tag. Walking on the support beams between sections of boards works well, though if you fall through then simply climb the ladder in the corner of the lower area to return.
Coalition Cargo
COG Tag 21
Right at the start of this chapter when you're in the cart control room, head down the short steps then turn around to find the tags next to them. Get this before hitting the switch to make sure you don't enter the carts automatically.
Darkest Before Dawn
COG Tag 22
After you ride the drilling platforms down, proceed forwards along the right hand path before you head down the slope to reach an area with the red emblem and an obvious tag on the ground.
COG Tag 23
Once you've slipped down the slope and fought off a wave of enemies, look on your right to find the next tag down the side of some steps.
COG Tag 24
After you spot the Corpser for the first time, look immediately to your right to find a tag behind a truck in the corner.