Welcome to this guide! As you will see, it's separated in sections, each one of which is connected to a chapter, except the last one. In all of them, I'll be describing the actions you need to do to each level to get all the achievements, so consider it a partial walkthrough!

I used the following guides as references and taking pictures from (credits to the creators):
https://www.trueachievements.com/game/Unravel/walkthrough
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2389824990
Now that I described what you need to know, let's go! Start the game as normal and dive in to the first level!

Gardener
Tear down all the thistles in one go.


For this achievement, you have to find all six thistles and pull them all down without dying (note: the last one isn't probably necessary). This level isn't too hard, so just be careful and you should be able to get this without too much trouble. So let's do that and also find the secrets at the same time!

1. When you reach the bird house and tie a knot to its node then on the branch to the right of it, don't jump up yet. Drop off to the right side and press [S] on your keyboard or [LT] on your gamepad a few times so that you don't fall to your death. Once you get to the bottom there will be a patch of thistles to the right. Pull them down; behind them is also the first secret. Climb back up and use the trampoline you made beforehand.
2. When you reach to a folding chair, run right under it to the right, fall down into the garden and you'll find a patch of thistles to the left with a ball of yarn behind it. Pull them down and remember to take the yarn!
3. Head to the right after taking the yarn and stay on the bottom under the sunflowers. To the right is another patch of thistles with the second secret behind them.
4. Go to the right after jumping up the sunflowers, and when you fall back down to the ground there is a patch of thistles obscuring a tricycle. Pull them to release the tricycle.
5. After the tricycle part, above you there are four nodes that you can lasso to make your way up the tree. One you're at the top of the fourth one, you'll have to launch yourself far to the right and lasso another branch. Tie a knot to this branch a climb down the yarn. In a small alcove to the right there will be the third secret. You may have to swing a little to get in the alcove.
Climb back up and swing to the ledge that is to the far right. Go right past the image of a girl in a tree house and there will be another thistle blocking some yarn. Pull down the thistle and don't forget to grab the yarn!
6. When you find the block, leave it by the sandbox and go to the right to find the final thistle patch that blocks the see-saw/teeter-totter. Pull them down and if you haven't missed any thistles, congratulations, you got the achievement!

Let's find the other two secrets now. After releasing the see-saw/teeter-totter, push the block to the right side of it first and it will drop the right side of it. Then run up the slope to the left and there will be a lasso node with the fourth secret. Now you can drop back down and bring the block back to the left side.
Ιnside the greenhouse, after getting and jumping on the block and then the thin wooden wall, don't jump to the right yet! Instead, jump to the left and onto a hanging flower pot. Here you will find the last secret of the level.
Now you can go back to the right, and a cutscene will take you to the end of the level and unlock a story achievement!

Missing piece
Find the first missing piece

Eagle Eye
Find the secret hidden in the tree tops where you fly


To get this achievement, you need to find the first secret of the level, hidden in the branches of one of the trees while riding the kite. Do NOT get the next checkpoint until you get the secret, otherwise you have to start the whole level over again to get to the same kite location. You might die a few times, or die after you get it, like me, but it will still count that you got it if you restart the level (when going for the "Not so fragile after all" achievement, more on that later). You can count the trees in the front or the back to help you spot it, I counted the trees in the front and noticed it's the third tree. Here's a video that personally helped me a lot:

If you succeeded and got the achievement, we're good to go find the rest of the secrets!
The second secret can be found in the water, at the left of the rock Yarny is standing at the image, down and left of the checkpoint. Get it quickly and get out before you drown!
After making it at the dock that you should tie a knot to, swing under the dock and get the ball of yarn. Continue to the left by pushing the piece of wood. Continue under the dock to the left and you'll come to a small alcove with the third secret.
After going at the right of the waves and then above them, at the third lasso node (it's just past the edge of the dock above you), tie a knot to it. Lasso to the node slightly to the left and tie a knot there. Next, climb down until you're almost touching the waves. It will be a little below the lasso node that is under the one you've tied a knot to. Then swing back and forth until you get enough momentum to reach the fourth secret.
When you make it to the boat house, grab the checkpoint but don't go on the boat yet. Make a trampoline on the two nodes to the left and jump up to another platform. Push the two boxes to the right, which will swing up the platform. On the ceiling, there are three hooks that you can swing from. (You can tie a knot to each one so you can just pull yourself back up.) There are also two pulley blocks in between the hooks that you will have to stand on. If you over shoot these you can pull yourself back up. When you get to the far right there is the fifth secret on a ledge.

Now that you got all the secrets in this level, you can start the boat and finish the level to get another story achievement!

Watch the waves
Find the second missing piece

Pacifist
Make it through the mire in one go without swatting any mosquitoes


This achievement is pretty much self-explainatory. Don't kill any mosquitos, don't die and you'll get it at the end of the level! Use your lasso only to nodes that are highlighted, else it'll automatically aim to mosquitoes. Now, to secrets!
Note: I somehow got the achievement even after I died a few times, so I guess you don't have to not die at all to get it! (Unless, again, you're going for the "Not so fragile after all" achievement.)

RIGHT at the start of the level, there is a the first secret hidden above you in the trees. To get up there, lasso the second node that you see and climb to the top of it. The node above you will shimmer, indicating that Yarny will be able to reach it if you grab for it. Quickly release [D] or [RT] and press it again. You can use this technique to go up to the next pair of branches but it's much easier to make a trampoline and use that to jump up there. When you get to the top pair of branches, make a trampoline and stand in the middle of it. If you stand to the sides you won't jump far enough. While you are in the air grab the node in the middle of the trees, and swing to the left to get the first secret.
After crossing the pool safely, get to the next checkpoint, but don't keep running; there is the second secret nearby. The rock in front of you will fall when you stand on it. So, run on it and jump back to the left before you get taken with it. If you do accidentally fall you can pull yourself back up by climbing up the yarn tail.
At the stove, use the node to pull open the stove door and two logs will come rolling out. There is a third log in the stove that you have to pull out. Push all three logs to the left, which will make the third secret pop out from the other side.
At the tractor, pull the lever to the right to open the front of it. Then use the lasso node on the front of the tractor to get on top of the engine compartment. From here you can push the smokestack to the left and climb to the top of the tractor cab. Up here there is a broken headlamp that you can push down to where the fourth secret is to obtain it, since it's unreachable otherwise.
After pushing the berry gatherer to the right, use it to jump to the next checkpoint; once you get here, there will be two branches above you with nodes on them. Make a trampoline with them (watch out, the left branch will fall a little), and jump to the left to get the last secret of this level.
Now that you got all secrets, finish the level and claim another story achievement!

Found at last
Find the third missing piece

Let's start off by finding the secrets this time.

When you get yarn after climbing some roots, head to the hole to the right and you'll start sliding. If you want to stop you can simply grab your yarn tail with [S] or [LT]. There is a water pit with the first secret towards the bottom that you might not be able to see at first. To get it, stand on the rock above it and get it to fall in the water. Then you can use the node and lower yourself down or swing down and to the right.
At the checkpoint where you can see a bird house to the top left, make a trampoline here and then jump up to the birdhouse and make another trampoline to reach the second secret.
At the right of the checkpoint after the boat ride, there are three nodes; tie knots to each one so they create a ramp going into the cave. Trampoline up and push the tin can into the cave using the ramp that you created. Once inside the cave you will see a large tilting log. Push the can to the right side of it first and go under the left side of the log to get the third secret. Then you can push the tin can on the left side.
After the lemming chase, climbing up the vines and getting a checkpoint, you will come to larger area with a more complicated series of paths. First, make a bridge/trampoline. Then climb up the vines on the right side and pull on the node to the right to release a rock. Then pull the wooden pail down and push it to the left. If it gets stuck just pull it back out and try again. Drop down to where the rock dropped and push it over to the first trampoline. Now make a bridge with the two nodes to the left and push the rock onto this ledge. From here you can jump up and get the fourth secret.
Finding this will also unlock another achievement:

Get a clew
Get the secret hidden in the mountain maze


After riding the bag and seeing another image, climb up a woodshed and pull open the door to release the logs. Try not to slam the door right on you and then run to the right. Lasso to the branch and climb up to get out of the way of the logs. Then head to the left and go inside the woodshed for the last secret.

Now that the logs are creating a bridge, cross them to end the level!

Walkabout
Find the fourth missing piece

Pathfinder
Make it to the water wheel without using a log raft


To do this achievement, you'll have to go to the water wheel WITHOUT using the log raft. However, to get the first secret, you need to break that rule and use the log raft. So, just follow the instructions below and then restart the section by using [end].

First, open the latch to the right while trying to stay out of the water. This works best if you don't jump at all when you lasso the node. Then tie a knot to the node inside, creating a bridge to the checkpoint. Push the log raft all way to the left and off the platform. Fall onto and ride to the first secret. Now you can restart the section.
Use the nodes to continue the level, until you reach the structure, where there is the second secret. While hanging over the water, swing over and get it. You may have to let go of [S] or [LT] as you're swinging to the right to get the proper distance.

Continue the level and you'll eventually unlock the "Pathfinder" achievement when you finish the section and haven't used the log raft! (If you're not sure how, check the following video. You can also see how to claim the second secret.)

Continuing with the secrets, after putting the wheel on the tilting board and grabbing a checkpoint, backtrack a little bit to get the third secret. Go left until you reach the gap with the tilting board and rappel down into the gap to find the secret on the right side.
After avoiding the rocks, climbing the vines, and jumping to an alcove, there will be a lasso node; don't climb up it, though. This jump can be a little difficult so it's a good idea to tie a knot to this node. Now use it to swing to the far right where there is another lasso node to grab the fourth secret.
After numerous checkpoints with rocks coming towards you, at the fourth one quickly lasso the branch on the ground and pull it back to shield yourself from the rock. Then lasso up to another checkpoint to get some more yarn. Head back to the left where the rock that you just block came from and climb up the hill some more for the fifth secret.

Now that all secrets are found, finish the level as normal to get another story achievement!

Everlasting
Find the fifth missing piece

Let's start off with the secrets again.

When you make it to the toxic water, jump over the first pool and lasso across the second one. After this there are two barrels being held up by a stick. Once you stand on the middle of the second barrel they will start rolling to the left. Jump back to the left before they get too far. Then pull the bottle out of the barrel. Behind it is the first secret.
After throwing the barrels in the water and swinging onto them, continue to the right until you see the second secret on a barrel. First get the checkpoint that is to the right of the barrel just in case, since the secret is dangerous to get. To get it, go back to the left and swing dangerously close to the toxic water. Once you get swinging, jump off to the right and get the secret.
Note: I found an easier way! Continue past the checkpoint and swing at the node above the toxic water, until a log bridge falls. It's close to you, so carefully grab it and drag it to the barrel. Use it to get the secret and then return it to its original position so that you can proceed!
Before plugging in the electrical cord, jump up and lasso a node off the screen to the right of the ladder in the background. Once you've lassoed it, swing to the left and jump onto the ladder. This will cause it to fall to the left and now you will be able to get the third secret on the lampshade.
After getting past under the crushing barrel and grabbing the checkpoint, continue to the right and you should be able to see the fourth secret below the sloped platform that you are on. Keep going to the right and drop down. Simply pull out the hard hat and get the secret to the left.
At the excavator, you'll see that the fifth secret is at the box, so you need to smash it with the excavator. Start by pulling the box all the way to the left and making a trampoline on top of it. Then jump off the trampoline and lasso a handle from the cab of the excavator. Tie a knot here and drop back down to the ground. Then push the box all the way to the right so that it's up against the shovel (do NOT pull the handle to drop the excavator bucket unless the box is in place or you'll have to start the entire level again); don't forget to untie the nodes in the box, else you won't be able to push it! Pull yourself back up the to the excavator cab with [S] or [LT]. Get on top of it, hold [S] or [LT] and swing over the seat to the two handles inside the cab. Push the handle under the seat to swing the seat back up and then pull the on above it to drop the bucket, which should destroy the box and the mound of dirt. From here drop back down to where the box was to get the fifth secret.
You'll also get an achievement:

Dig where you stand
Use the excavator to find a secret


Run to the right, swing once and finish the level!

Scarred earth
Find the sixth missing piece

Starting off with the secrets once again, you have to deviate from your normal path. After the checkpoint, instead of going up, drop off and quickly grab the first node to the left. This next section can be very difficult but there are a few hints that will help immensely: always tie a knot to every single node. And from here, until you get to the last ring, always hold [S] or [LT]. Make sure the next node is highlighted and briefly let go of [D] or [RT] and immediately press it again. You should ALWAYS continue to hold down [S] or [LT]. Continue like that and on the last node, you will have to swing a little so continue to hold [D] or [RT] and then release [S] or [LT]. Swing until you get enough momentum, then release [D] or [RT] to get the first secret. Here, it is probably best to just reload the checkpoint so you don't have to bother going back through that mess and return to the normal path.
Once you're out of the hole, you will be under a rock with a node on it. Jump up to the right side of the flat rock nearby. Lasso the node and pull the rock down. This will launch you at the second secret. If you land a little short go into the alcove to the left.
At the powering lines section, start by running right to the first ceramic insulator and then up the lines to the left. Tie a knot on the node here and swing over to the satellite dish for a checkpoint. (Make sure you don't accidentally get shocked while swinging to the right.) This will automatically create a trampoline if you tied a knot to the previous node. Now use the trampoline to jump over the satellite dish to the left to find the third secret. Now you can climb your yarn tail to get back to the checkpoint.
At the second checkpoint inside the crushing, zapping death machine, go to the left past the crushing piston and get back onto a node to the left. Here you can swing to get the secret. Alternatively, you can just jump off the piston to the left and you can hit it, but you'll probably die.


You'll also get the following achievement:

Undaunted
Find the secret in the crushing, zapping death machine


After scaring the crow away, go to the left and pull out the bottom drawer all the way. Now pull out the drawer that was above it to get the last secret of the level.

Now wrap up the level and claim another story achievement!

Shut down
Steal the sixth missing piece back

Obsessive
Break all the ice on the way to the letterbox in one go


To get this achievement, you have to break all the ice patches (don't worry, you don't need to not die at all, just don't restart the level). There are 12 in total, but most of them are together, so let's show their locations along with the secrets!

1 & 2: Start the level by going to the right. Down a steep hill will be the first patches of ice. They take two jumps to break and it's possible to get stuck or drown if you fall into some of them. On the second jump, quickly jump again to safe ground so you don't have to deal with that. The water here isn't deep enough, but it's difficult to jump out of it once the ice is broken!
3. Head a little more to the right and you'll come to a road with a tiny patch of ice.
4, 5 & 6. Just a little more to the right there are three more patches of ice.
7, 8 & 9. Further to the right, after passing through the seesaw/teeter-totter, there is another river with 3 patches of ice to destroy.
Once you get inside the building, there is a block on the ground in front of you. You'll need to get this block all the way to the upper right corner of the screen to get the third secret. You have to make several bridges with yarn to be able to push it all the way up there, and also use those bridges as trampolines in order to make more bridges. (For a more detailed way to do so, check here[www.trueachievements.com].) Continue so until you lasso the club hammer: it will fall over and you should be able to see the secret behind it. Tie one last bridge to the handle of the club hammer and drop down to the bottom. If everything was done correctly, you should be able to push the block all the way up to the secret.
On the hooked pulley block right of the checkpoint inside the barn, lasso the node, pull it to the left and use it to swing to the light's pull switch. From here you'll have to swing to the far left; on the screen to the left, there is a paint can that you want to push the right so it's on the ground. Drop down to it but make sure you hold onto your yarn tail or the fall will kill you. Keep pushing the paint can to the right under the hay wagon to some more paint cans for the second secret.
After this, climb back up your yarn tail to go back to the previous checkpoint. From here tie a knot on the pulley block. Then swing over to the top of the lampshade to the left and make a trampoline there. Jump up to the attic and head right to find the third secret in the bird nest.
From where you just found the secret, go out the window to the right and rappel safely down the building. Head to the right where there is a covered well. Pull up both hatches by lasso and open the well. Tie a knot to the left node on the well and rappel down to grab the fourth secret.
Past the gate and to the river, break through the first patch of ice to reveal a log that can be pulled to the left. Then tie a knot to it which will create a trampoline. Jump off the trampoline to the branch above and, using the node at the top, swing over to the fifth secret on the right.
10, 11 & 12. Drop back down and destroy the last three patches of ice, being careful not to drown in the process.

If you broke all the ice patches, then congratulations, you've successfully unlocked the "Obsessive" achievement! Now finish the level and claim another story achievement!

Reach out
Find the seventh missing piece

Snowfall
Clear all the snowy branches in one go


To get this achievement, you have to clear every snowy branch you see! There are too many to put pictures of, so I'll inform you that there are at least 32, but you need 29 to unlock this achievement! So, clear as many as you can (again, you don't need to not die at all) and you'll get it! I won't tell you where to find each branch since, again, there are so many, but click here[www.trueachievements.com] for the exact locations!
As you will see, most branches are visible, so I think you'll be able to find them even without this link! Either way, good luck! Now, to the secrets!

At the cave, head left out after getting the checkpoint, and climb up the branch above you again. Make a trampoline here and jump up to the branch above you (which will be cleared from the snow for the "Snowfall" achievement). Right above the node on this branch there is the first secret that is completely concealed. If you have trouble getting it here, you can get it when you are on top of the branch later.
Next, head to the left, jumping on the branch pointing towards the foreground and on the branch pointing to the left. Then lasso the node above you and tie a knot here. This is just to get back from the next step. Jump to the left two snowy branches. Now, jump off to the left and lasso the node before you fall completely. Swing over to the second secret on the branch to the left and then jump back on the pine tree to the right.
Note: You might be able to get this secret first if the fourth branch covered in snow flings you up there; but since this isn't always reliable and you can't reload the checkpoint to try it again, if it doesn't work, just continue and you can claim it with the way I described above. (Technically, that makes the second secret first and vice versa.)
After the next checkpoint, tie a knot to the first node and make two bridges with the next two nodes. Knock the pinecone off the tree above the left trampoline and push it to the right. You will enter a cave and the snowball will be able to break the ice. From the checkpoint hold [S] or [LT] and swing to the left below it to find the third secret.
At the checkpoint after the toboggan ride, keep going right over two branches and use the node above you to swing to another checkpoint. Keep going right and there will be a snowy branch above you (by the first rock). Climb up it on the right side and go left to where the snow is. Hopefully this will fling you twice and get the fourth secret on the branch far to the top right; if you don't succeed, you'll have to restart the entire level again, so pay attention to physics!
After pushing the snowball into the kettle, it will swing the pot holder lever up. Climb up it, lasso the antlers mounted on the firewood shed and tie a knot to this node. From here let out a lot of slack and then swing to the right to get the fifth secret.

By this time, if you have also unlocked the "Snowfall" achievement, you'll be good to climb back up to the antlers and head right to finish the level!

Cold but warm
Find the eighth missing piece

Let's start with the secrets again.

At the second stack of tires (not the first with the checkpoint), lasso the node to the upper right side and make a trampoline with this and the next node. It's a little difficult to get to the node with this trampoline, but it's up and to the right. Once you get to it, tie a knot. Then let out enough slack that you are almost to the trampoline. Start swinging back and forth until you get enough height to get the first secret to the right.
At a checkpoint after the gas tank, swing over on the hanging node to another node on a small platform. Tie a knot to this node. (Notice that there is a secret above the target, we'll come back for that in a little bit.) Swing off while holding [S] or [LT] to get to the can hanging from a string. To the right there is another can on a string. Push the thing hanging from it so it drops down. Now you can make a trampoline and jump up to the checkpoint. From the checkpoint, jump off the right side, go to the left under the checkpoint and you'll get the second secret.
Remember the secret that was above the target? Now it's time to get it! Climb up to the checkpoint and lasso to the right. Then swing a little and lasso to the right one more time. Now you will have to let out some string. Swing back and forth until you get a lot of momentum. Then get ready. Jump off to the left with as much momentum as you can. This should take you close to the third secret. Make sure to hold [S] or [LT] when you are falling, or else you'll die!
After getting that secret, return to the node you used to get there, but swing right this time to reach the window; get inside and grab another checkpoint. Here, you'll do a puzzle with a crane magnet. Drop down to the left of the car and you will see a foot pedal on the right with four buttons to the left of it; you'll use these to activate and move the magnet. First, bring the magnet down into the car to pull out a steel block. Then bring it over to the left where you came in. When it's all the way to the left, turn off the power to the magnet with the foot pedal. Then pick the block back up and climb up to the fourth secret that was inside the box.


Taking this secret will also unclock an achievement:

Reckless
Find the secret in the engine room


At the second checkpoint inside the car crusher, run to the right very fast and open the trunk/boot by pulling the latch. When inside, go to the bottom of the front seat. Pull it back so it folds down. Then, while on the top of the seat, lasso the glove box to get the fifth secret.


Quickly jump up to the window and press the button to the right to stop the car crusher. When you're done go to the right to finish the level!

Time will catch up
Find a broken half piece

The end is not the end
Find the other broken half piece


Since there are no secrets in this level, all you have to do is play and finish the level to get this story achievement!

Flow
Use your lasso to jump between 25 different points without touching the ground


In this level there a lot of glowing orbs that you can use your lasso on, so just keep lassoing through as many as you can without touching the ground and you'll get the achievement! It's not hard and you don't get any fall damage! You can also try to do it while looking for the secrets.

Now with that out of the way, let's find the secrets!

At the start of the level, go to the right and lasso the node to get flung up. Then there's another orb that will take you over a pool of water. To the right there will be a rock that you fly over with a birch in the foreground. The next tree in the background has the first secret at the top of it. Be careful, if you go off to the sides too much you'll get launched into the wrong direction!
Next, drop down to the ground and run to the right. You will come a vertical stump that is still in the ground. From here lasso up and to the right several times to get to the second secret. This one is much easier to get than the last one, just try not to swing too violently.
Continuing on, you'll soon get to a part where there are no more high nodes that you can reach. It's a field with lots of white flowers and a blue haze in the background. From here there is something that looks like a ditch a little further to the right. From here you want to go up and to the left and follow the path of orbs. It will lead you back to the tree that you recently passed. It seems best to make short lassos so you don't swing to wildly. The third secret is on a branch, obscured by some leaves.
Continue on the ground to the right until you get to a fallen log. All you have to do is hold [S] or [LT] and drop down to a little log boat.
From the fallen log, there is another secret to the upper right, sort of near the top of tree that snapped.


If you have found all 55 secrets, then CONGRATULATIONS, YOU UNLOCKED THE SECRETS ACHIEVEMENT!

No stone unturned
Find every secret


Finish the last level and finish the game to get the final story achievement!

Renewed
Mend a broken bond

If you followed the guide correctly, you should have two achievements left.

Νot so fragile after all
Finish each level from start to finish without dying


For this achievement, I don't have a lot to say. You have to make it through all the levels without dying (except chapter 12, in which it is impossible to die). That means you have to get through one level at a time without dying; if you die, you'll have to restart the entire level over again. Levels that you have done this will have a small crown on the picture frame, so you'll know which ones are valid for the achievement. Just keep practising and have patience. If you make it, you'll also automatically get the final achievement:

The red thread
Collect all achievements



CONGRATULATIONS, YOU GOT 100% OF THE ACHIEVEMENTS!
I hope this guide helped you!