Here is the full list of all 38 Castaway Paradise Complete Edition achievements.
Grow every type of fruit
Donate all fish
Donated every collectable
Donate all shells
Rebuild the Lighthouse
Collect 25 pieces of garbage
Remove 50 weeds
Rebuild Gustave's Bakery
Read 50 chit chats
Make a profit of 5000 gems on the Stock Market
Grow every type of crop
Donate 15 shells
Rebuild Francis' Pirateshack
Rebuild Amelia's Planehouse
Remove 25 cobwebs
Live the luxury life of a VIP
Rebuild Angus' Trailer
Wore an outfit of the opposite gender
Remove 25 stones
Rebuild Victoria's Mansion
Make a profit of 500 gems on the Stock Market
Completed 100 quests
Donate 15 fish
Make a profit of 2000 gems at the Bank
Used every piece of equipment
Unlocked a gate
Harvest 50 crops
Donate all bugs
Changed every piece of outfit
Unlock the second room in your house
Donate 15 bugs
Donate a collectable
Rebuild Harold's Museum
Rebuild a bridge
Completed 25 quests
Get your first collectable
Completed the tutorial
Grow every type of flower