Here is the full list of all 21 Cornucopia Demo achievements.
Steam Train was Spotted
Defeat the Spider Boss
Get Stuck in the Waterwheel
Earn 10,000 Gold
Try Every Scratch Card
Catch your first Large Fish
Harvest your first Fruit Tree
Harvest your first Berry Bush
Harvest your first Vegetable
Brush an Animal
Refine 10 Times
Catch your first Fish
Discover the Old Mines
Give your first Gift
Bomb an NPC
Plant your first Seed
Pass out from Exhaustion
Decorate your Home for the First Time
Feed Munger for the First Time
Open your first Letter
Catch 10 Fish