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