Here is the full list of all 28 Nevrosa: Primal Ritual achievements.
Kill first Spider
Kill 50 spiders
Kill 100 spiders
Kill 250 spiders
Kill 500 spiders
Kill first Shooter
Kill 10 shooters
Kill 50 shooters
Kill 100 shooters
Kill the first lazer flower
Kill 3 lasers
Kill 10 lasers
Found first circle of spiders
Found two circles of spiders
Found three circle of spiders
Activate all Engines
Find first obelisk
Find three Obelisks
Find seven Obelisks
Find all obelisks
Find the first Statue
Find three more Statues
Find all ancient Statues
Complete the First Ritual
Complete the Second Ritual
Complete the Third Ritual
Complete all Rituals
Leave the Misty World