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