Here is the full list of all 21 Schein achievements.
Died in fire 100 times.
All collectibles found.
Listened to the secret dialog.
Completed Schein.
Left the lantern behind.
Died on spikes 100 times.
Kept the blue light lit for 60 seconds.
Defeated Ermatu.
Caught a lantern mid-air 25 times.
Ride platforms for a total of 5000 meters.
Kept the red light lit for 60 seconds.
Died in water 100 times.
Half of all collectibles found.
Defeated Sartasis.
First collectible found.
Defeated Zenel.
Kept the green light lit for 60 seconds.
Met the Irrlicht.
Walked left at the beginning.
Completed Schein with less than 100 deaths.
Completed Schein with less than 50 deaths.