Here is the full list of all 51 Courier of the Crypts achievements.
Collect flame while ghost timer is in progress
Kill 10 enemies without attacking them.
Have 10 spiders following you at once.
Step on 10 critters.
Turn off wooden mechanism.
Destroy the wooden machine using only rocks.
Finish the Sewers map without getting hurt.
Finish The Mines without using the torch.
Go through the Shattering Halls timed event without getting hurt.
Stop spider infestation for good.
Steal the key from the cultists without getting noticed.
Finish the Library without using any weapons on enemies.
Take down the authority in the Lost Caverns.
Eradicate the living roots.
Send guardian of the Fire Sanctum back to darkness.
Use the monocular.
Follow thy Flame and overcome darkness
Throw one in for a luck!
Pay a visit to the Graveyard of Patrons.
Read the most boring book in the crypts.
Try something...different.
Dig a grave
Visit the ancient dweller...
Finish the game
Finish 1 level with perfect score.
Finish 5 levels with perfect score.
Finish 10 levels with perfect score.
Find all relic pieces in 1 map.
Find all relics in 5 maps.
Find all relics in 10 maps.
Read 5 texts.
Read 20 texts.
Read 40 texts.
Find your first secret place!
Find 15 secret places.
Find 40 secret places.
Destroy 10 objects.
Destroy 50 objects.
Destroy 100 objects.
Purchase your first item.
Purchase 6 items.
Unlock your first secret map.
Own more than 9000 gold.
Get killed by a ghosts after running out of flame.
Effectively use 20 Magic Seeds on enemies.
Braaaaaaiiiiinnnnnnssss...
Get a 100% complete rate on your profile.
Purchase at least 5 bundles of ammo.