Here is the full list of all 29 Marlow Briggs and the Mask of Death achievements.
Watch all credits
Complete the game on any difficulty
Kill enemy with each magic
Defeat HellHound
Defeat the Air boss
Kill enemy with each weapon
Fly across the chasm
Solve the temple puzzle
Defeat the Water boss
Gain entry to treasure room.
Solve the water puzzle
Perform a 50-hit combo
Find a collectible
Execute an enemy
Survive train-cart ride
Launch enemy and kill it before it falls on ground
Kill enemy with air combo.
Destroy 10 enemies using only spirit knives
Kill enemy with enviromental objects (fire, barrel,...)
Defeat the Fire boss
Earn upgrade point and spend it
Knock enemy off ledge into their falling death
Kill enemy with deflected projectile
Get your first achievement
Block enemy attack.
Complete the game on Hardcore difficulty
Glide for more than 6 seconds
Skip all cutscenes in one play through
Find all collectibles in one play through