Here is the full list of all 22 Smushi Come Home achievements. It takes around 4-5 hours to unlock all of the achievements on Windows.
Acquire all wind essences
Acquire all spores of energy
Craft every skin
Beat the diver challenge
Discover every mushroom
Beat the nectar gathering high score
Talk to the onion
Unite both capybara siblings
Rescue Chungy
Collect 400 crystals
Restore all flower shrines
Beat both obstacle courses
Help a friend gather two acorns
Rescue both lost lovers
Cleanse the corruption
Explode the river drain
Collect 200 crystals
Beat all three glider game challenges
Feed the lizard two berries
Collect 100 crystals
Knock down all the strawberries
Bring both relics to the researcher