Here is the full list of all 31 Deadlight achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Finish the Nightmare mode
Beat the high score in Madness Mansion
Get 100% of Deadlight
Make it to the end
Finish Randall's flashback
Find all of Randall's memories
Find all the IDs
Reunite with Stella
Finish Randall's nightmare
Beat the high score in Sport Daisy
Find Parker in the hockey arena
Face someone from Randall's past in the Park
Get infected by a friend on the leaderboards
Beat the high score in Raven Thunder's Rock Legend
Find the first health expander
Follow the Ratman to his den
Finish Randall's dream
Perform a headshot
Kill an enemy with a single melee attack
Push a zombie over a railing
Reload the revolver really fast
Get to the military control
Tackle an enemy
Perform a combo on an enemy
Reach the junkyard
Execute an enemy
Tackle a door
Escape from the warehouse
Roll to avoid lethal fall damage
Survive a close encounter
Find a page of Randall's journal