Here is the full list of all 43 Tinykin achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Be lunch for a carnivorous plant
Go back to Aegis with Salvior Ardwin
Make friends with all the tinykin in the house
Hatch a tinykin egg using another tinykin
Talk to Ghasper in each room
Collect all the pollen in Foliana
Collect all the pollen in Sanctar
Collect all the pollen in Transidor
Help Wolter organize the race in Celerion
Help Sikaru with all his brews
Find all the artefacts stolen from Prattle's museum
Collect all the pollen in Celerion
Post every letter in the house
Light all the candles in the house
Put back all the books on the messy shelves in Celerion
Get the big wheel spinning in Celerion
Get behind the scenes in the house
Collect all the pollen in Ambrose
Prepare Ardwin's Cake for Seross in Ambrose
Break the biggest ice cube in Ambrose
Avoid drowning in extremis
Destroy 300 objects with explosive tinykin
Empty the sink in Ambrose
Sneak into the pantry in Ambrose
Unlock the safe upstairs in Transidor
Fix the giant clock upstairs in Transidor
Survive a fatal fall in extremis
Break the damaged Matryoshka doll upstairs in Transidor
Steal the pollen from the voracious plant in Transidor
Collect all the pollen in Balnea
Get the party started in Balnea for Partipupa
Mistreat the house's inhabitants 100 times
Light up the dung beetles' lamp in Balnea
Reposition the nose on the fountain in Foliana
Liberate the funnel from Offrocker in Foliana
Light all the candles in a room
Help Sikaru prepare his first brew
Give Sanctar's sphinx its nose back
Let Ardwin's Canticle ring out across Sanctar
Rebuild the frog in Sanctar
Post every letter in a room
Find one of the artefacts stolen from Prattle's museum
Free the passage under the stairs in Transidor for Ridmi