Here is the full list of all 22 Remnants of Naezith achievements.
Complete the Metal chapter
Find a secret
Speedrun the Sand chapter
Complete the Sand chapter
Speedrun the Jade chapter
Play a Custom Level
Master the Jade chapter
Complete the Jade chapter
Customize your appearance
Inspect a top player
Watch a replay
Improve your time
Complete the Crystal chapter
Complete all the chapters
Master the Sand chapter
Master the Metal chapter
Master the Crystal chapter
Master all the chapters
Speedrun the Metal chapter
Speedrun the Crystal chapter
Speedrun all the chapters
Find all the secrets