Hold your patience, we just got 7 collectibles in ACT 4. So let’s move a bit faster.
ACT 4 : Get out
1. Locust shell disposal form (Obj: Return to the ore transporter)
In the beginning you need to drop through two ledges. After the second one, you will find a yellow metal crate. Take a left from there and you will end up with another yellow metal crate. The form lies there.
ACT 4 : No detours
2. Col Tag K.Rush (Obj: Get to the dam)
Advance the game until you come across a gear that stands against the wall to the left of the path. The soldier’s body and the tag will be present a few steps after the gear.
ACT 4 : Knock knock
3. COG orders (Obj: Get to the dam entrance)
Go on with the game until you reach the entrance of Tollen Dam in front of you. Turn left and climb up the platform. Then take a right and you will find the orders at the far end of the room.
ACT 4 : Powerless
4. COG Tag P.Wood (Obj: Head back inside)
After a short battle, you will open double doors. Proceed on the path untill you reach a control room to the left. Once you enter the room, go to other side of the console. There you will find the tag.
5. Rations schedule for abandoned gears (Obj: Find a way to the top of a dam)
Progress in the game until you come across giant moving chains. Go ahead until you find a wall with “13E” written on it. Take a left to the wall and you will find the schedule behind some boxes.
ACT 4 : Storm warning
6. COG Tag E.Yates (Obj: Find a way through the substation)
First you need to go through the storm and make it out alive. Then you will enter a substation. After you enter go to the room to your right. You will find the corpse and the tag on a desk.
7. Letter (Obj: Find a way through the substation)
Once you destroy the first coil, advance until you come across sandbags. Leap over and you will find the letter there.
And you get to see the video here