Here is the full list of all 25 Witching Tower: Heroes achievements.
Complete Necro-Ritual
Complete Ancestors Cemetery
Complete Source of the Darkness
Complete Necro-Ritual on Nightmare
Complete Ancestors Cemetery on Nightmare
Complete Source of the Darkness on Nightmare
Complete 3 missions with Lightforged Sword and Purging Shield
Complete 3 missions with Triforce Bow
Complete 3 missions with Firelight Wand and Orb of Health
Complete 3 missions with Spiral Drill and Blasting Pistol
Gain score multiplier x30
Gain 1000000 points
Complete the mission without getting hit
Complete the Source of the Darkness without Obelisk taking damage
Destroy 25 Protective Shields in Necro-Ritual missions
Destroy 30 Coffins in Ancestors Cemetery missions
Kill 15 Bosses in Source of the Darkness missions
Beat 35 waves on Survival mode
Сollect 100 power-ups
Activate 50 traps
Die from self damage, including traps activated by the player
Kill 30 Mages
Kill 30 Knights
Kill 100 Dogs
Kill 30 Jesters