Here is the full list of all 20 It Takes Two achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
You did it! CO-LLA-BO-RATION!
You reached a higher state of mind. Or at least some peace and quiet.
Release that tension at the root level.
Again? Keep track of your kids!
Choo Choo!
Guess it was time to cash out.
Put on a show and die trying.
Shoot for the stars, literally.
Self-inflicted paparazzi.
It takes two to… torture.
All minigames found!
They had no way out.
The truth was out there all along!
Now look who's extinct!
Isn't it pretty? That's going on the fridge.
Helltower? More like hello-from-up-here-tower!
Breathe some wind into your ocarina, my skyward princess!
Took things a bit too far, didn't you?
Don't feed the animals! Or do, they're adorable.
Scurvy! Ye look smashing, captain!