In Caves of Qud, there are a total of 100 Steam achievements awarded for completing certain tasks. Of these 100, 35 are hidden, meaning that neither the requirements for completion nor the achievement's icon are displayed until after the player has completed them. These hidden achievements are displayed further down, in a separate section from the non-hidden achievements.
Through some method, gain a reputation of +600 or more with one of the in-game Factions.
This can generally be achieved most easily by becoming loved by the player's starting village, as you can water-ritual with the Mayor, the town's Warden, and the town's Questgiver.
From there, you must either kill creatures disliked by the village, perform a Water Ritual with creatures liked by the village, or use Schrodinger pages from the Annals of Qud to increase your reputation further.
Another easy-to-please faction is Mechanimists, just toss enough artifacts in the sacred well at the Six Day Stilt. For example 8-9 laser rifles which are relatively easy to gather/tinker, but give a respectable +75 reputation per offering.
Absolute Unit
Successfully cook a meal with neutron flux as an ingredient.
Become as Gods
Bestow life to 20 inanimate objects.
Belong, Friends
Help the slynth find a new home.
Biographer
Learn the complete history of a single sultan.
Learn every piece of historical gossip about the life of a single Sultan.
Thus, if you have it, it is a good idea to use Precognition (or a sphynxsalt injector, if you are True Kin) before activating your timecube, so that you can earn the achievement and still have a timecube to cast into the sacred well.
If you have it, it is a good idea to use Precognition (or a sphynxsalt injector, if you are True Kin) before offering to the well so that you can gain the achievement and still keep your artifact.
Eat an Entire Bear
Kill a bear and eat it. Just eat an entire bear.
Kill a bear and eat its corpse raw by picking up the bear corpse, waiting until you are famished or hungrier, and choosing to eat it.
Players with the Carnivorous (D) mutation need not wait until they are famished.
Feast Upon the Goat Hearts! *cheers*
Perform the water ritual with Mamon Souldrinker.
Friend to Fungi
Host 3 different fungal infections at once.
Become the host of 3 different types of fungal infection.
This can be easily achieved by walking near three differently colored broodpuffs. Make sure that one fungal infection has grown before walking near the next broodpuff, as itchy skin does not stack and walking into more spores will not change the infection type.
Killing Svenlainard is, for obvious reasons, an expedient. He is not affiliated with the Village of Kyakukya, so you do not need to worry about others joining in the fight unless you have area of effect moves. However, dominating him and forcing him to drop his swords also works.
Perform the water ritual with a legendary frog, and request that it teach you a skill. (Legendary frogs teach Jump.)
This is a very rare achievement, mostly due to the relatively low chance that you will come across a legendary frog lair and have enough reputation for them to teach you Jump, most especially before training the skill yourself. ice frog lairs are generally located in the jungle biome.
Live and Ink
Tattoo yourself.
Lottery Winner
Gain a mutation from a gamma moth's mutating gaze.
Mouse control is required for this achievement, as looking through keyboard commands means the cursor will always start to centered on yourself, making you fall in love with yourself before you have a chance to look at a sign. Turn on mouse controls, apply love injector, and right click a sign to look at it.
Love Thyself
Fall in love with yourself.
Inject yourself with a love injector and look at yourself.
May the Ground Shake But the Six Day Stilt Never Tumble
Travel to the Six Day Stilt.
Mechanimist Reformer
Convince the High Priest of the Stilt to join your party.
Somewhat difficult to attain, due to the rarity of Newly sentient beings. Reputation is mostly achieved from Schrodinger pages and water ritualing creatures that are loved by newly sentient being and killing creatures hated by them.
Proteus
Have 10 mutations.
Through some method, gain a total of 10 mutations.
This can be easily done by creating a character that has a 4 point defect and choosing all the cheapest mutations possible.
Get damaged by a neutronflux explosion or similar effect, such as the explosion caused by failing to examine an tier 8+ artifact with Dystechnia (D) or the explosion created by baetyls and sparking baetyls when at low health.
Proselytize or beguile a soupy sludge, and dump 3 different liquids on it. Then wail on the helpless thing. It must be a Trisludge: any more and it will not count.
Five-Sludge Monte
Kill a pentasludge.
Kill a soupy sludge composed of 5 different liquids.
Ten-Sludge Monte
Kill a decasludge.
Kill a soupy sludge composed of 10 different liquids.
Token of Gratitude
Be gifted a 10-pointed asterisk.
To Thine Own Self Be True
Wear your own severed face on your face.
Through some method, manage to get your face severed off, regenerate it, and then equip your severed face in your face slot.
This can also be achieved via the Evil Twin (D) mutation.
Tourist
Visit 100 generated villages.
tsk tsk
Disappoint a highly entropic being.
Two Cats Are Better Than One
Clone Ctesiphus.
Was It Something I Said?
Invoke the Chaos Spiel.
What's Eating the Watervine?
Complete the quest What's Eating the Watervine?
What With the Disembowelment and All
Find one of Argyve's old apprentices.
Spot the flattened remains. They are located in the center zone of a random salt marshparasangAn area made of 3x3 screens, which is represented as one tile on the overworld map..
Your Thirst Is Mine, My Water Is Yours
Perform the introductory water ritual 100 times.
Make a habit of performing the water ritual with all the NPCs in your starting village after beginning a new game and this should not be too difficult to complete.
Hidden Achievements
Aaaaaaaaargh!
Overdose on a hulk honey tonic.
A Clammy Reception
Enter Mak's clam in the Yd Freehold.
Aetalag
Be turned to stone.
All Those Who Wander
Travel to the pocket dimension Tzimtzlum.
Cosmo-Chrononaut
Enter 25 spacetime vortices.
The easiest way is to take Space-Time Vortex at character creation and use it at every opportunity. This is an aggregate number so it can be done across playthroughs.
In addition, you can be decapitated by a Decarbonizer's decarbonize effect, an axe-wielding dervish, or by an Evil Twin (D) if you know decapitate or are wielding a relic that has a chance to decapitate. If you only have one head, losing it will kill you unless you have Regeneration at level 10.
Jeweled Dusk
Be transmuted into a gemstone.
Litteratus
Read 10 books.
When finding a book in the world, make a habit of choosing to read it before putting it in your inventory. You need only look at the first page of a book for it to count as read.
So Powerful is the Charm of Words
Read 100 books.
When finding a book in the world, make a habit of choosing to read it before putting it in your inventory. You need only look at the first page of a book for it to count as read.
Note that Ironshank must actually be contracted. Using honey or yuckwheatstems to stave off the disease after getting the "Your legs ache at the joints" message will not count.
Note that Ironshank must actually be contracted in order to be cured. Staving off the disease using honey or yuckwheatstems will prevent you from contracting the disease and thus prevent you from curing it.
Randomly generated thermoelectriccells occasionally contain some lava inside, which is usually easiest way to get it without spelunking 30 strata deep to kill a redjell or getting lucky with an ichor merchant. Then just drink that good juice. Note: this usually deals enough damage to kill you instantly.
Psst.
Find the oddly-hued glowpad.
Find the oddly-hued glowpad in the salt marsh. They will be located in the center zone of a random salt marshparasangAn area made of 3x3 screens, which is represented as one tile on the overworld map..
Red Rock Hazing Ritual
Be stoned to death by a baboon on the surface of Red Rock.
Note that Glotrot must actually be contracted. Using honey or yuckwheatstems to stave off the disease after getting the "Your throat feels sore" message will not count.
Note that Glotrot must actually be contracted to be cured. Staving off the disease using honey or yuckwheatstems will prevent you from contracting the disease and thus prevent you from curing it. This also counts for the Synolymb achievement.
Shoot.
Get killed by a chute crab.
Easily done if entering Golgotha blind. For a dedicated build for this, take Precognition and Wings, fly to Golgotha, and precog until you find the shaft with scratched vents, and wait.
Choose the "Your hair is a quasar of red ochre and indigo." option while talking to Q Girl.
The Recitation of the Drowning of Eudoxia by the Witches of Moonhearth
Wear the Otherpearl.
Welcome to Qud
Die.
Somehow, perish. This can be caused by being reduced to zero HP or by several methods of instant death.
You Are Becoming
Install a cybernetic implant at a becoming nook.
As a True Kin, find a becoming nook and install one of the cybernetic implants found nearby.
A becoming nook is guaranteed to appear at the bottom-most stratum of the Rusted Archway.
You Became
Have a cybernetic implant installed on every implantable body part.
A becoming nook, which will allow True Kin to install cybernetics, is guaranteed to appear at the bottom-most stratum of the Rusted Archway.
Finding credits to install them all is the hardest part. However, they can be farmed by scouring the deserts for Putus Templar parties. After completing, Tomb of the Eaters will also increase the player's license by 8.
You Are What You Eat
Eat one of your own limbs.
Get dismembered (voluntarily or not), and eat your raw dismembered limb or other body part. Cooking with your dismembered body part as an ingredient does not count towards this achievement.
Your Better Half
Get killed by your evil twin.
Get killed by one of your evil twins, which will occasionally appear when entering an unexplored map tile if you have the Evil Twin (D) defect.
Precognition or, if you are True Kin, a 
sphynx salt injector before dying will still award the achievement.
timecube, and then activate it. A time cube is one of the few artifacts which can earn the achievement Donation Level: Kasaphescence when cast down into the 
sacred well.
bear and eat its corpse raw by picking up the 
bear corpse, waiting until you are famished or hungrier, and choosing to eat it.
Caslainard & 
Polluxus, 
Svenlainard, Trophy Hunter's two electrified longswords.
Mamon Souldrinker and equip the 
amaranthine prism that he drops.
Dominate a 
goat.
Oboroqoru, Ape God and then perform the water ritual with them.
Stopsvalinn can be easily gained from trading secrets from the Barathrumites or Trolls.
love injector and look at a 
sign.
chrome pyramid. See Chrome pyramid/Killing.
alchemist, an NPC found in the depths of 
Bethesda Susa.
neutron flux explosion or similar effect, such as the explosion caused by failing to examine an tier 8+ artifact with 
Dystechnia (D) or the explosion created by 
baetyls and 
sparking baetyls when at low health.
helping hands. Or, 
beetlebum
Phase back into the corporeal realm inside a wall which is completely surrounded by other walls.
Ruin of House Isner. Methods on finding the pistol is located on its page.
sludge composed of 3 different liquids.
flattened remains. They are located in the center zone of a random 
salt marsh parasangAn area made of 3x3 screens, which is represented as one tile on the overworld map..
Space-Time Vortex at character creation and use it at every opportunity. This is an aggregate number so it can be done across playthroughs.
Corpus Choliys.
thermoelectric cells occasionally contain some 
lava inside, which is usually easiest way to get it without spelunking 30 strata deep to kill a 
red jell or getting lucky with an 
ichor merchant. Then just drink that good juice. Note: this usually deals enough damage to kill you instantly.
oddly-hued glowpad in the 
Golgotha blind. For a dedicated build for this, take 
Wings, fly to Golgotha, and precog until you find the shaft with 
scratched vents, and wait.
Regeneration, entering a 
regeneration tank, or applying an 
ubernostrum injector after losing a limb. Regenerating a tongue to cure Glotrot also counts for this achievment.
Q Girl.
becoming nook and install one of the cybernetic implants found nearby.
Rusted Archway.
Evil Twin (D) defect.
