Here is the full list of all 30 Deadlight achievements worth 400 gamerscore. It takes around 6-8 hours to unlock all of the achievements on Xbox 360.
Get 100% of Deadlight
Find all of Randall's memories
Make it to the end
Finish Randall's flashback
Find all the IDs
Reunite with Stella
Beat the high score in Madness Mansion
Finish Randall's nightmare
Find Parker in the hockey arena
Beat the high score in Sport Daisy
Face someone from Randall's past in the Park
Follow the Ratman to his den
Roll to avoid lethal fall damage
Beat the high score in Raven Thunder's Rock Legend
Finish Randall's dream
Push a zombie over a railing
Perform a headshot
Reload the revolver really fast
Get to the military control
Find the first health expander
Reach the junkyard
Perform a combo on an enemy
Execute an enemy
Kill an enemy with a single melee attack
Tackle an enemy
Survive a close encounter
Tackle a door
Escape from the warehouse
Find a page of Randall's journal
Get infected by a friend on the leaderboards