Here is the full list of all 15 Quell 4D achievements.
Waste 15 Ancient Triple Trunked Elephant Necro Shamans
Splat 10 Slugs attached to your face with the Shredder
Own Necronomicus
Travel to space
Drink 10 Blood Bags
Waste the Drone Queen
Pick up five guns
Prune 3 Slugs that have attached to your face.
Exterminate 20 Slug Drones
Cook a Beefcake with the RPG
Smash 50 Slug Eggs before they hatch
Kill the Ratfox Commander
Kill 100 Animals
Boom 15 enemies with explosions
Wear two helmets at the same time