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.
Craft every skin
Beat the diver challenge
Talk to the onion
Unite both capybara siblings
Rescue Chungy
Collect 400 crystals
Discover every mushroom
Acquire all wind essences
Cleanse the corruption
Acquire all spores of energy
Beat the nectar gathering high score
Rescue both lost lovers
Help a friend gather two acorns
Explode the river drain
Beat all three glider game challenges
Beat both obstacle courses
Collect 200 crystals
Knock down all the strawberries
Restore all flower shrines
Feed the lizard two berries
Collect 100 crystals
Bring both relics to the researcher