Here is the full list of all 28 EMPTY SHELL: DEMO achievements.
Kill 350 Small Spiders
Kill 10 Spitting Spiders
Kill 400 Walking Soulless
Collect all the documents in the Prologue
Kill 350 enemies with the Old Axe
Death count: 10
Death count: 1
Use a Device
Find 5 secret rooms
Rounds fired: 200
Rounds fired: 100
As big as an elephant
Kill the Hand in less than 20 seconds on NIGHTMARE difficulty
Deploy a Gadget
Upgrades Cost: >1000
Complete the Demo
Complete the Demo on Nightmare difficulty
Complete the Demo on Hard difficulty or higher
Complete the Demo on Medium difficulty or higher
Complete the Demo on Easy difficulty or higher
Survive the whole Prologue on NIGHTMARE difficulty with the same volunteer
Kill her with her own weapon
Find 5 documents
Leaving Building C
Finish a level without taking any damaged on NIGHTMARE difficulty
Finish a level with only melee weapons
Kills count: 50
Kills count: 15