Collectible #21 - Anvil Gate Plaque
After the cutscene with Hoffman and you are back in control inside the fort, make a quick 180 degree turn and you will see the Anvil Gate Plaque on the wall.
Collectible #22 - Watercolor Painting
From the main area where you start in the fort at Anvil Gate, make a run up the right side staircase and follow the walkway around to a large room. Enter the room on the right and there will be a huge painting on the wall. Take a peek at it to get this rather sneaky collectible.
Collectible #23 - Sam’s Fathers Medals
When you reach the far end of the fort and are defending the first gate against the Locusts, take a trip to the other side of the walkway and make a left down the passage way. You will pass a couple rooms on the right side, but the last room on the left will have these medals on the ground in the corner.
Collectible #24 – Journal
When you are fighting the LambentZerker, go straight forward from the gate that you entered and there will be a large circular structure in the center of the area. Make your way around it to the far side and you will find the journal there along with an ammo crate.
Cog Tag #9
During the Lambent Zerker fight, put your back to the gate that you came through and look to the left. In the corner, below the Blood Omen on the wall, there will be a stack of barrels and the cog tag will be on the ground. The Zerker will be attacking while you are in this area, so lure it away to grab the tag without taking a hit.
Collectible #25 - Panicked Note
After the scene with the crazy old man, head down the stairs on the left side and follow the landing to the far side. On the ground there will be a scorcher and the collectible note will be right beside it.
Cog Tag #10
When you are tracking down the old man through the town, you will come to a doorway that has boards across it. Saw through or break them down and head inside. Go to the right and follow the corridor around to the left to find the cog tag on the ground in a room to the right.
Collectible #26 – Message
The game menu states that this is found in chapter 5, but it is actually found in chapter 4, right near the end, just after you climb the ladder to reach the top of the building after the swarm of lambent come attacking. You will have a Vulcan gun to help you ward off the onslaught of enemies, and then when they are gone kablooey, you’ll climb the ladder to meet the stranded there. Before you go too far after climbing up, make a left down the corridor there to find the paper at the very far end.
Collectible #27 - Air Raid Shelter Sign
Once you enter the church, make your way to the left side and saw or break through the boards. Hop down to the catwalk and make a left to find the sign on the wall there.