A list with how to get all the achievements.
I'll list the achievements in chronological order. After every group of levels there is an animation, move time around in the animation till something starts moving, then wait a few seconds. There are no missable achievements, during your playthrough or after you can go back to a level and get the achievement you did miss.
If you beat the game under 2 hours, please don't be a jerk and refund. Support this wonderful developer and keep this little gem in your collection!
Level 2 (Front Door):
After completing the second level you get an animation with the 2 friends before the front door. Keep moving left and right till the door lights up and wait a few seconds before it opens.
Level 4 (Children Pool):
After completing level for you can move around in an animation again, move around till the top of the cool-box lights up and wait a few seconds for it to open.
Level 5 (Table with Jenga):
Reset The Dominos
With the second device you can manipulate the time to first let the domino fall and after that rewind to get it back up.
Level 6 (Television):
In the video game on the big screen with the chicken you have to let the chicken die.
Level 7 (Couch):
At the second point where you can change the time, stop the lantern holder under the table cloth and walk forward to let the table cloth fall over the lantern holder.
After beating level 7, there is a new animation. Move the time forward and backwards till you have hit Frendt 5 times with the popcorn.
Staying Up Late
In the same animation as the achievement above, keep moving time forward and backward till the television start glowing. Wait a fec seconds for a crow to come out of the television.
Level 8 (Saw):
Saw Through Time
Keep jumping on the saw till the plank is broken.
Level 10 (Treehouse):
At the top of the level you can use the lift to get Arina to the bottom of the level.
Our Secret Clubhouse
After level 10 in the animation move the time forward and backward till the poster lights up. wait again for a few seconds.
Level 12 (Dinosaur Skeleton):
In the animation after level 12, move around till the egg starts moving, wait a few seconds for this achievement to unlock.
Level 15 (Jacket):
An Expedition Goes Down The Drain
After level 15 in the animation move around till the ring on the left pipe starts moving. wait a few seconds and the achievement will pop.
Level 17 (Music Player):
When you get the light back in the last puzzle of this level, instead of running up, run a bit back down where the purple smoke was and reveal what is behind it.
Level 18 (Telescope):
Reach For The Sky
At the final puzzle of this level you need to hold your empty lantern over the moon to capture the light.
After level 17 in the animation, move around the time till the telescope starts moving, and wait a few seconds.
Don't touch that!
There is a device with a green screen. Stop with Arina behind the device and wait till the lightning hits the device.
End of the Game:
The Gardens Complete
You get this after beaten the game, while you did, please enjoy the song during the credits <3 I love it!