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