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