Also, they aren't easy to find. At all to be honest.
Below are the Serpent Emblem locations for Ada's campaign.
#1 - This emblem is found to the right of the bunk room. This is after the alarm section. Look for it above some steps that have yellow/black caution tape on them, just under a small light.
#2 - This is on the other side of a large column in the room where Ada plans her escape. Hard to explain, but it's there. Just search this room (look for a control box of sorts).
#3 - Climb the ladder after escaping the flood. Once on top, head left and crawl under the small opening to find this emblem. It's just beyond this enemy next to a yellow ladder. Look for the large fan as a marking point.
#4 - Run past the bug monster here and go through the door. The emblem is on top of two pipes at ground level.
#1 - Head to the open grave at the beginning of this chapter to find this emblem. It's on the other side of it.
#2 - Unlock the door via the three crest pieces and head through the now open door. Drop down, turn around, and look up and left. It's there on top of a column.
#3 - Take the elevator down to the lab after helping Helena and Leon. Open the door here and crawl through the space on your left. There will eventually be some boxes you can break. No, the emblem is not in them. Instead, look to your right. Boom.
#4 - Drop down into the water and turn around. It's behind you on the wall. You'll know which point I'm talking about - trust me.
#1 - Head to the city street and you'll find the emblem hanging up by some belts at the store.
#2 - Keep going through the chapter until you find a green van on fire (not to be confused with man on fire). The emblem is on the other side of this van, just to it's left near a fence.
#3 - Wait for the bus to stop and look to the left. It's there.
#4 - After Ada jumps from the train you'll simply head into the next building. Go down the stairs until you reach a dead end.The emblem is behind a crate in the lower right corner of this hallway.
#1 - Just past the first spotlight is a place for you to grapple. Go up here and look left to see the emblem.
#2 - Head farther into the ship after Carla falls to find this one. Kill the enemy and search the lockers Borderlands-style. It's of course in the last one you can search on the very left.
#3 - Don't go down the hatch before you look to the left of it. The emblem is here.
#4 - Don't freak out when the giant face tries to eat your eyes. Instead, turn left here and you'll find the emblem on some pipes near a white and red box. If you proceed through the door you've gone too far.
#1 - Finally we get to be in a helicopter. Suckers! Use the turrets to shoot the emblem here in the back of the yellow truck (it's towards the driver's side window).
#2 - During the helicopter fight, look towards the very lit up building to your right. It's on top of a large vertical white sign with red letter). About two floors down from the rooftop of said building.
#3 - Before saving the second group of civilians, head to the left side of the building they are trapped on. The emblem is located here, fairly far down.
#4 - After you grapple onto the piece of equipment attached to the crane you'll want to face the building to your right. The emblem is located in the distance here. It's not that easy to spot, but it's there.