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