33 Unlocked Achievements:
-Passed the Trial: Finish the game on any difficulty.
-Ran the Gauntlet: Finish the game on the "Blood and Broken Bones!" or "Death March!" difficulty levels.
-Walked the Path: Finish the game on the "Death March!" difficulty level.
-Geralt: The Professional: Complete all witcher contracts.
-Dendrologist: Acquire all the Abilities in one tree.
-The Enemy of My Enemy: Use the Axii Sign to force one opponent to kill another. Do this 20 times.
-Humpty Dumpty: Kill 10 opponents by knocking them off somewhere high with the Aard Sign.
-Environmentally Unfriendly: Kill 50 opponents using the environment (e.g. swamp gas, insects or objects).
-Kaer Morhen Trained: Perform 10 effective counterattacks in a row without getting hit or parrying.
-Can't Touch This!: Kill 5 foes in a fight without taking damage (except for Toxicity) and without using the Quen Sign.
-That Is the Evilest Thing: Ignite the gas produced by a Dragon's Dream bomb using a burning opponent. Do this 10 times.
-Butcher of Blaviken: Kill at least 5 opponents in under 10 seconds.
-Brawler: Defeat Olaf, the Skellige champion of unarmed combat.
-Overkill: Make an opponent suffer from bleeding, poisoning and burning simultaneously. Do this 10 times.
-Master Marksman: Kill 50 human and nonhuman opponents by striking them in the head with a crossbow bolt.
-Globetrotter: Discover 100 fast travel points.
-Pest Control: Destroy all monster nests in the Velen / Novigrad region, or in Skellige.
-Card Collector: Acquire all gwent cards available in the base version of the game.
Gwent Master: Defeat Tybalt and win the gwent tournament held at the Passiflora.
-Let's Cook!: Learn 12 potion formulae.
-Bombardier: Collect the formulae for 6 different bomb types.
-Bookworm: Read 30 books, journals or other documents.
-Armed and Dangerous: Find and equip all the elements of one set of witcher gear.
-Power Overwhelming: Have all possible Place of Power bonuses active at the same time.
-Brawl Master: Complete all fistfighting quests in Velen, Skellige and Novigrad.
-Fast and Furious: Win all the horse races in the game.
-Munchkin: Reach character development level 35.
-Fire in the Hole: Destroy 10 monster nests using bombs.
-Fist of the South Star: Defeat an opponent in a fistfight without taking any damage.
-Geralt and Friends: Win a round of gwent using only neutral cards.
-All In: Play three hero cards in one round of gwent and win the match.
-Even Odds: Kill 2 monsters you have a contract on without using Signs, potions, mutagens, oils or bombs.
-Mutant: Fill all mutagen slots.
There's also 19 sercet achievements that say: "Continue playing to unlock this secret achievement"