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