Here is the full list of all 31 Stranger Things 3: The Game achievements worth 1,000 gamerscore.
Beat the game on New Game+
Complete the game
Complete Mall Showdown
Found all 50 hidden gnomes.
Complete Cabin Ambush
Complete 30 Minutes or Less
Unlock Steve
Unlock Erica
Complete Invasion of Privacy
Complete Hospital Brawl
Unlock Will
Found 25 hidden gnomes. Half-way there!
Unlock Eleven
Unlock Hopper and Joyce
Complete Chores for Granny Perkins
Successfully hack the hardest level chest/door
Unlock Max
Complete Revenge of the Geeks
Complete Ivan the Smuggler
Unlock Jonathan
Unlock Nancy
Complete Wall Flower
Acquire 5 trinkets
Complete Rats in the Walls
Complete Store Raid
Complete On the Wire
Complete Break In, Make Out
Complete Radar Love
Crafted your first item
Unlock Dustin
Complete Sneak Peek