Here is the full list of all 40 Dead achievements.
Complete DEAD with Easy Mode, Boss Rush Mode and One Hit Mode enabled
Complete DEAD with Boss Rush Mode and One Hit Mode enabled
Complete DEAD in Easy Mode
Kill Dying Ember on Easy Mode
Kill The Silenced before killing Migraine
Summon the second ring
Only use explosions when killing Dying Ember
Kill Scourge without exploding
Never take damage from the clock
Ring the bell
Do not dodge when fighting Puppeteer
Never dodge when fighting Glass Master
Do not dodge when fighting Totem
Never fire a bullet or explode when fighting Totem
Kill Vesicle without leaving the bridge
Kill Progenitor without moving
Kill Dying Ember
Do not destroy any crystals
Kill Eight Bears
Kill Eight Bears using only explosions
Kill Eight Bears in Easy Mode
Kill Scourge
Kill The Silenced
Kill The Silenced within 60 seconds
Kill Totem
Kill Puppeteer
Never take damage when fighting Glass Master
Never take damage when fighting Migraine
Never allow Smelter to get the sword
Never allow Vesicle to heal
Kill Eremite first
Kill Progenitor without exploding
Kill Glass Master
Kill Migraine
Kill Eremite and Spectre
Kill Furnace
Never dodge when fighting Furnace and Smelter
Kill Vescile
Kill Progenitor
Dead