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