To make it easy and fast, just put game on easiest difficulty and shoot everyone who sees you. You can go to menu after finding your collectable item. No need to play whole map.

Hopefully this guide will help somebody.
Chapter 1: Just before you go to room where the shrinkray is, there is a small box on a wall with text "mycop" open it and you will find first collectible.

Chapter 2: Quite early when you need to find server room, instead of going left from picture 1, go to right and you will see stairs. Go under them and pick VHS that is on the small table. (Does not show in picture because i accidently picked it up before taking picture)

Chapter 3: After the first lazers, use elevator to go up, jump on a box and you find lazer pointer on top of it.

Chapter 4: After you find spytacles you come to this room. There is a Vial on table right side of the room.

Chapter 5: From beginning go to the right, you will see a booth. Go inside it and you find drinking bird collectible.

Chapter 6: Do not start boss event. Instead just go left until you see some big box and barrels on left. There is a Lenin statue behind that big box.

Chapter 7: After you escaped big russian hulk guy you will find this room. You can find snowglobe on the table.

Chapter 8: Very early before you meet first guard, you will see some paintings on wall. Pick 2nd painting on left side of the room. (Does not show in picture, because i picked it up before screenshot)

Chapter 9: Simply turn around at beginning to find this collectible.

Chapter 10: Climb up to the room where you need to defuse nuke. Collectible is this big chip on the ground.
Chapter 11: Keep playing until you reach DDR Tunnels. Soon you will see doorway in picture 1, go left from there and you will see big discoball on couch. Pick it up and you are done with this achievement.