Here is the full list of all 31 Stranger Things 3: The Game achievements.
Beat the game on New Game+
Found all 50 hidden gnomes.
Found 25 hidden gnomes. Half-way there!
Complete the game
Complete Mall Showdown
Complete Cabin Ambush
Complete 30 Minutes or Less
Complete Invasion of Privacy
Unlock Steve
Unlock Erica
Complete Hospital Brawl
Craft 5 trinkets
Complete Chores for Granny Perkins
Unlock Will
Complete Revenge of the Geeks
Unlock Eleven
Successfully hack the hardest level chest/door
Unlock Hopper and Joyce
Unlock Max
Complete Break In, Make Out
Complete On the Wire
Unlock Jonathan
Unlock Nancy
Complete Rats in the Walls
Complete Store Raid
Complete Ivan the Smuggler
Complete Wall Flower
Complete Radar Love
Crafted your first item
Unlock Dustin
Complete Sneak Peek