Here is the full list of all 32 Stranger Things 3: The Game trophies - there are 16 bronze, 10 silver, 5 gold and 1 platinum.
Unlock all trophies
Beat the game on New Game+
Found all 50 hidden gnomes
Complete the game
Complete Mall Showdown
Complete Wall Flower
Complete Cabin Ambush
Complete Invasion of Privacy
Complete 30 Minutes or Less
Unlock Steve
Unlock Erica
Found 25 hidden gnomes. Half-way there!
Complete On the Wire
Complete Hospital Brawl
Unlock Will
Acquire five trinkets
Complete Ivan the Smuggler
Complete Store Raid
Unlock Eleven
Unlock Hopper and Joyce
Unlock Max
Complete Rats in the Walls
Complete Chores for Granny Perkins
Successfully hack the hardest level chest/door
Complete Break In, Make Out
Unlock Jonathan
Unlock Nancy
Complete Radar Love
Crafted your first item
Unlock Dustin
Complete Revenge of the Geeks
Complete Sneak Peek