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