4 missable achievements (plus 108 unknown)
Sign in with Steam or Xbox to track your progress, and:
Kill Brutus, Warden of Axiom Prison.
encountered as you go through the prison in the first act, around level 9ish.
Kill Merveil, the Siren.
The 2nd achievement-providing boss in the game.
Defeat Piety in her laboratory.
Equip a Unique item.
Kill Voll, Emperor of Purity.
Shatter 5 monsters with a single action.
Slay an enemy that is simultaneously Ignited, Shocked, and Frozen.
Kill Maligaro, The Inquisitor.
Kill Doedre Darktongue.
Kill Shavronne of Umbra.
Vanquish the Vaal Oversoul.
Open a Vaal Vessel in a corrupted zone.
As you get toward the end of act 1, after the prison, you should start to see random caves in a red hue; corrupted caves. Explore through, kill the mini-boss and loot the place; there will be a vaal vessel in the middle of the room.
Fully clear the Ship Graveyard Cave.
Free the Scion.
Kill Dominus as the Witch.
Allocate a Keystone Passive Skill.
Land the killing blow on the Burning Man while you are burning.
Equip a Rare or Unique item in every non-Flask slot.
Kill High Templar Dominus.
Kill Malachai, The Nightmare.
Complete the Labyrinth in a non-Hardcore league.
Fully clear an end-game Map area.
Have at least 75% resistance to Fire, Ice and Lightning.
Fully clear the Archives.
Join a public party.
Choose an Ascendancy class.
Complete Part 1.
Kill Dominus as the Ranger.
Kill a god and obtain their power.
Open a Large Chest.
Fully clear the Dread Thicket
Kill Dominus as the Duelist.
Kill Tsoagoth, the Brine King
Reach level 60 as a non-Hardcore character.
Kill Dominus as the Marauder.
Kill Dominus as the Shadow.
Kill Dominus as the Templar.
Kill Arakaali, Spinner of Shadows.
Kill a player in a Cut-throat league.
Fully clear the Catacombs.
Equip a Unique Jewel with a radius.
Kill both Lunaris and Solaris in the same encounter.
Complete the Cruel Labyrinth in a non-Hardcore league.
Open a map in the map device and step through its portal.
Kill the Depraved Trinity.
Reach level 70 as a non-Hardcore character.
Complete a Forsaken Master's daily mission.
Hand in a Full Set of Divination Cards to Tasuni.
Complete Part 2.
Kill a Rogue Exile in Kaom's Stronghold.
Obtain every Pantheon power.
Complete the Merciless Labyrinth in a non-Hardcore league.
Kill Izaro and have him drop 3 treasure keys.
Kill Dominus as the Scion.
Fully clear the Apex of Sacrifice.
Complete each side-quest.
Reach level 80 as a non-Hardcore character.
Equip two unique items with the same name.
Have 3 Totems alive at one time.
Use an orb to change the mods of a Strongbox.
Corrupt an item to have a new implicit mod.
Have a Unique Item drop in the Twilight Strand.
Reach level 8 in any Race Event.
Kill the Eater of Souls in the Core end-game Map.
Corrupt an item to have a white socket.
Upgrade a map with a Shaper's Orb.
Enhance a map with a Vaal fragment.
Have a Skill Gem reach level 20.
From right near the beginning you'll find gems you can slot into weapons/armour. These gems have a level. As you keep using the item (e.g. hitting people with the weapon), the gems will gain XP and level up too.
Note that weapon gems will gain XP even if you don't actively use the ability/attack that the gem provides (e.g. flaming arrows).
Complete the Eternal Labyrinth in a non-Hardcore league.
Corrupt a map to have eight mods.
Land the killing blow on the Vaal Oversoul while you have the Fortify Buff active.
Fully clear The Harvest.
Have at least 90% resistance to any Element.
Allocate a character's fourth Keystone Passive.
Finish the Labyrinth in a Hardcore League.
Corrupt an Essence monster with a Remnant of Corruption.
Reach level 90 as a non-Hardcore character.
Complete all of the white maps on the Atlas.
Have a Vaal Skill Gem reach level 20.
Same as for a regular gem; socket it in...
Complete a map area that is affected by 10 or more mods. This can include mods from Sextants and other mods that are not on the map item.
Have a Unique Map drop within a Unique Map.
Find all of the Shaper's Memory Fragments.
Craft a Jewel with four mods using an Orb of Alchemy.
Complete the Eternal Labyrinth in a Hardcore League.
Create an item with six linked sockets using an Orb of Fusing.
Kill Abaxoth, The End of All That Is.
Fully clear the Colosseum end-game Map.
Help all three Bandit Lords.
Corrupt a Unique Jewel into a different Unique Jewel.
Have 9 Raised Zombies alive at one time.
Reach level 60 as a Hardcore character.
Finish the Cruel Labyrinth in a Hardcore League.
Corrupt a skill gem into a Vaal skill gem.
Complete all of the yellow maps on the Atlas.
Reach level 70 as a Hardcore character.
Tag each waypoint.
Have 60 Minions at the same time.
Reach level 80 as a Hardcore character.
Finish Merciless Labyrinth in a Hardcore League.
Corrupt a map into a Vaal Temple map.
Create a Unique item using an Orb of Chance.
Kill the Shaper.
Complete all of the red maps on the Atlas.
Reserve 95% or more of your Life.
Defeat the Pale Council.
Reach level 90 as a Hardcore character.
Listen to all optional NPC dialogue.
Capture a flag during any CTF match.
Discover all environmental lore.
Defeat Sirus, Awakener of Worlds.
Kill all Warbands leaders.
Have 15 combined Endurance, Frenzy, and Power Charges active simultaneously.
Kill Atziri in the Alluring Abyss.
Complete the Hall of Grandmasters.
Kill every Breachlord.
Kill a monster that is under the influence of five Essence mods.
Have four Watchstones socketed in each Region of your Atlas.
Complete every map on the Atlas.
Level 7 Forsaken Masters to their maximum level.
Fully upgrade every god power.
Equip each Maraketh Weapon type.
Accept The Maven's Invitation and defeat The Maven.