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