There are exactly 2 types of achievements in the game:

• 4 of them require you to collect artifacts, with a 5th for finishing the game with all of them.
  
• 10 of them require you to find these flying creatures, also with an 11th for finding all of them.
  
  
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Getting all 10 of them is supposed to unlock:


There's lots of reports about this achievement bugging out though.

Everyone agrees, that by playing through the entire game in one continues playthrough, and collecting all 10 critters in chronological order while doing so, the game will unlock the final achievement properly. Either at the 10th location (which was the case for me), or on the transition to the credits.

Beyond that though, I've found a lot of contradicting statements all over the place.
Most people still agree, that you can safely use the chapter selection to grab missed creatures, as long as you haven't yet played and finished the final chapter 10.
I can confirm that this was true for me personally, as of the publication date of this guide. I'll let you know though, that I've found 2 statements claiming this to not be the case.

From here on out, it becomes very vague. Some people claimed, that they could easily grab the missing ones through chapter selection after finishing the final chapter, and getting the achievement at whichever place they collected their 10th.
Some people claimed, that they still had to collect the one at the chapter 9 spot on top, as only that spot supposedly checks for "All Together".
Some people claimed, that they really had to go for all creatures anew, though by using chapter selection, they only had to play up until the critters went flying, then being able to jump straight to the next relevant chapter, with only the final chapter being required to be fully finished again.
And then we're back to the original statement, where people claimed, that nothing apart from a completely new playthrough would do it for them.

Tl;dr
Either follow this guide on your first playthrough, or be prepared for potentially doing up to an entire second playthrough.

Start at:

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Make your way through the level, until you're passing by this tree log:

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Pull the log as far left as the game allows. Climb onto it, then the branch above:

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Start at:

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Late into the chapter, after 2 cave sections, you'll get to this skeleton. Hurry along it's full length and grab the creature, before the skeletons falls:

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Continue to play through chapter 3, until you find these ruins. These are just before the next achievement further below, so you can easily find this by backtracking 10ish seconds, if need be:

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From there, just climb down to your left:

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Unmissable spot:

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From the screenshot above, make your way to the right, drop down at the earliest opportunity, then just walk back left, until you find this black hole thingy:

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Go right in front of the black hole and press the interaction button. Now traverse the low gravity area until you get to this spot at the end. Jump and the achievement unlocks.

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Start at:

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Play through the chapter until this climbing section:

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Go up and quickly climb through this opening in the wall to the right:

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The flying creature will be right in front of you:

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Start at:

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Very shortly after you've passed the flying sky whale, you'll get to this spot:

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Instead of jumping onto the mushroom, grab onto the climbable ivy and make your way down:

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Continue through the chapter until this spot:

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As with the first artifact, go right, drop down at the earliest opportunity, then make your way back to the left:

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At the end of the path, you'll get to the next black hole thingy:

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Press the interaction button, complete the zone, and grab the achievement at the end of it:

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After the achievement above, go back to this intersection. Take the upper right path this time:

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Soon after, you'll find this spot. Instead of jumping over to the yellow plants, drop down instead:

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At the bottom, you'll find the next creature:

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Start at:

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Early on in the level, you'll have another run-in with the big guy. Very shortly afterwards you'll come across this spot. Preferably play through the level during the daytime, as it makes it far easier to recognize this place:

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Use your time manipulation to climb the plant:

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You should know these by now. Find the huge structure:

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Find the first opportunity to climb down:

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Then make your way left as early as possible; in this case through this cave:

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Find the black hole:

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And complete the low gravity area:

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Continue through the stage until crossing through the pond:

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Soon afterwards, you'll have to drop into the hollow tree trunk during the hide-n-seek and quickly grab the creature to the left:

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Start at:

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After the lengthy indoors section, you'll pass behind a waterfall. You'll then find this climbing section with a huge aircraft in the background:

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Climb down the ivy, then crouch through the opening to the right:

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From there it's unmissable:

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Start at:

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This is the last flying creature you'll have to collect. So this should also unlock All Together. If it doesn't, refer to the opening section of this guide.

Make your way to this cliff:

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Halfway through the climb, jump off to the right and go to this red crystal:

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You're gonna have to run from an avalanche:

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Instead of climbing down the newly opened path, jump back to where the avalanche started and go all the way to the right:

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Alright, final artifact time. As before, find structure:

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Find way down:

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Find black hole to the left:

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Interact and complete area:

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Start at:

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Simply make your way to the end of the game. If you've collected the four artifacts in chapters 3, 6, 7 and 9, the achievement will unlock.

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