Here is the full list of all 30 Inmortuae Metuunt: Rise of The Undead achievements.
Kill 300 demons with a melee weapon.
Survive 1 Round in Palmares
Survive 1 Round in Challenger
Kill 100 Demons in one game
Complete a Arms Race game
Buy your first perk
Complete the Tutorial
Reach round 100
Kill 1000 demons in one game
Use all perks slots
Complete "Palmares" Easter Egg
Complete "Challenger" Easter Egg
Kill yourself with explosions or fire
Meet "him"
Play with a friend
Reach round 50 in "Palmares"
Reach round 50 in "Challenger"
Hold Heavenly Power
Reach the Holy reward level in "Palmares"
Unlock the "Apocalypse" in "Palmares"
Unlock "Daemonium Prototype V2" in "Challenger"
Use the Hell Rift
Reach round 50
Turn the power on "Base 05"
Use the Hell Rift on a character's starting weapon
Interact with DGP Mundo
Unlock Baltazar's Glorious Solution in "Palmares"
Unlock Ice Teaport in "Challenger"
Reach the maximum reward level with any of the horseman in "Challenger"
Kill 50 Boss Demons