Here is the full list of all 16 Demons with Shotguns achievements.
You collected 500 souls!
You earned 3 Monster Kills.
You earned 5 Double Kills.
You completed Ghosts n' Nomeds.
Flawless Victory!
You're an a' hole with how much you taunt.
You kept killing yourself.
You used 10 tarot cards in one match.
You don't seem to understand how ammo pickups work.
You jumped 100 times in one match.
You earned a Antichrist kill streak.
Fighting for scriptures.