This guide only contains information of some of the secrets in Shadow Warrior 2. I have already confirmed that there are more to be found. But with this guide you will know where to look and for what to look for when hunting that "I'm a Collector Myself" achivement.
Do also take notice that the maps in Shadow Warrior 2 is generated with various chunks. For finding some secrets you may have to revisit the mission again. That can be true for "Hot Blooded" as an example.
Some secrets can also be accessed in multiple missions. But even if found in different mission it will only count as one secret found. The guide contains 50+ different secrets and a location to find them, keep that in mind.
The original goal of this guide was simply the 50 secrets for the achivement but I might add more as time passes. Otherwise happy hunting.

At the spawn go to the waterfall, and enter the nearby cave.



After the long jump turn left at the intersection.



Hidden behind the alter.

Hidden within a cave corvered by a bush.



First find the entrance to the cave.
Once you have entered the cave turn left and break the wall.



Hidden in the bushes behind the statue.



Hidden in the bushes. Look for bridges and 3 trees standing close together.

Hidden in the trash.



Find the entrance.
Once inside drop down and go down the tunnel.
At the end of the tunnel break a hole in the wall and enter to find the secret.



Hidden behind the waterfall.



Find the entrance.
The secret is hidden behind the back right pillar.

Find the entrace to the cave. It can be seen in the lower left corner. It'll be near the giant temple. You can get there by walking around, dropping down from above or just jump over.
Head inside and you'll find the secret to your right in some webs.



Find the entrace to the cave. There are multiple entrances one is in a pit.
Once inside turn right and you'll find the secret.

Find the entrance to the cave.
Head inside and go toward the cages near the wall.
Then go behind the wooden planks and drop down the ladder.Once down break a hole in the wall.
Head inside and go down the ladder to your right.
You'll now have to jump up to the secret. The secret will be located to your right when you enter the room.



Find the entrance to the cave.
Go inside and turn right.
The secret will be to your left. You just have to jump up to it.



Find the statue and go around it.
You'll find a cave behind it. Go inside and you'll find the secret

Go through the tunnel hidden behind the leafs on the wall.



Jump through the wall painting to find the secret room.



Go through the eleator door outside of Kamiko's room.

Go around the tower and head inside.



Enter Kamiko's room and in the corner of the room you'll find it.



Follow the outer wall. (On the second floor if I remember correctly)



Follow the inner wall.



Find the marks on the wall. Look for a huge red cylinder if you can't find them.
Then jump down on the roof and go along it.
Looking back will look like this.
Continuing along the roofs will lead you to the secret.



Follow the wall and around the corner you'll find it.



Go around the building.

Find the entrance to the cave and head inside.
Once inside turn right and drop down.
Then break a hole in the wall and you're there.



Once you find the mark continue a bit further and you'll drop down.
Turn around and enter the cave on your left.



Once you reach the checkpoint turn around and head up.



Once you reach Mizu's house look for this panel on the right side of the lower floor.
Jump through and here you are.



Enter the river and look in the streams direction.



Go through the hole and you'll find it. Might be a little drop.



Go to the left of the bridge and take a look.



Hidden in the river under the bridge.



Once you crossed the bridge turn around and enter the tunnel.
Head inside and there it is.



Head upstairs and you'll find it.



At the gate of the palace look left.



Go to the right of the palace entrance.
Jump down on the platform to your right.
Turn around and there it is.



Go to the left of the palace entrance.Go straight for a bit and you'll see a platform to your right.
Jump down and there it is.

Under the huge bridge.
Go through the bushes and you'll find a little cave.



Jump up on the roof and go around the left corner.



Enter the cave hidden behind the waterfall.



Go around the pillar.
Make a hole in the wall and go through.

Behind the waterfall.



Go around the right side of the building.
Head into the bushes behind the building.



Behind the boxes in the coner.



Go up the stairs and follow the railing.



At the front door of the mansion. Follow the wall to the right.

Drop down and break the wall to your left.



Jump across the platforms and look right.

Find the island and go left around it.
Once you find this platform jump down.