4 missable achievements (plus 105 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.
Shatter 5 monsters with a single action.
Slay an enemy that is simultaneously Ignited, Shocked, and Frozen.
Kill Voll, Emperor of Purity.
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.
Vanquish the Vaal Oversoul.
Fully clear the Ship Graveyard Cave.
Kill Doedre Darktongue.
Kill Shavronne of Umbra.
Kill Maligaro, The Inquisitor.
Free the Scion.
Equip a Rare or Unique item in every non-Flask slot.
Allocate a Keystone Passive Skill.
Land the killing blow on the Burning Man while you are burning.
Kill Dominus as the Witch.
Join a public party.
Fully clear the Archives.
Kill High Templar Dominus.
Complete the Labyrinth in a non-Hardcore league.
Kill Malachai, The Nightmare.
Fully clear the Dread Thicket
Fully clear an end-game Map area.
Kill Dominus as the Ranger.
Open a Large Chest.
Have at least 75% resistance to Fire, Ice and Lightning.
Kill Dominus as the Marauder.
Choose an Ascendancy class.
Complete Part 1.
Kill Dominus as the Duelist.
Kill Dominus as the Shadow.
Fully clear the Catacombs.
Kill a god and obtain their power.
Reach level 60 as a non-Hardcore character.
Equip a Unique Jewel with a radius.
Kill Tsoagoth, the Brine King
Kill a player in a Cut-throat league.
Kill Dominus as the Templar.
Kill Arakaali, Spinner of Shadows.
Complete the Cruel Labyrinth in a non-Hardcore league.
Open a map in the map device and step through its portal.
Complete a Forsaken Master's daily mission.
Kill a Rogue Exile in Kaom's Stronghold.
Hand in a Full Set of Divination Cards to Tasuni.
Kill both Lunaris and Solaris in the same encounter.
Reach level 70 as a non-Hardcore character.
Kill the Depraved Trinity.
Complete Part 2.
Kill Dominus as the Scion.
Obtain every Pantheon power.
Fully clear the Apex of Sacrifice.
Complete each side-quest.
Complete the Merciless Labyrinth in a non-Hardcore league.
Reach level 8 in any Race Event.
Equip two unique items with the same name.
Corrupt an item to have a new implicit mod.
Reach level 80 as a non-Hardcore character.
Have a Unique Item drop in the Twilight Strand.
Kill Izaro and have him drop 3 treasure keys.
Use an orb to change the mods of a Strongbox.
Corrupt an item to have a white socket.
Kill the Eater of Souls in the Core end-game Map.
Land the killing blow on the Vaal Oversoul while you have the Fortify Buff active.
Upgrade a map with a Shaper's Orb.
Have 3 Totems alive at one time.
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.
Finish the Labyrinth in a Hardcore League.
Enhance a map with a Vaal fragment.
Fully clear The Harvest.
Corrupt an Essence monster with a Remnant of Corruption.
Allocate a character's fourth Keystone Passive.
Complete all of the white maps on the Atlas.
Complete the Eternal Labyrinth in a Hardcore League.
Reach level 90 as a non-Hardcore character.
Have at least 90% resistance to any Element.
Help all three Bandit Lords.
Have a Vaal Skill Gem reach level 20.
Same as for a regular gem; socket it in...
Have a Unique Map drop within a Unique Map.
Finish the Cruel Labyrinth in a Hardcore League.
Reach level 60 as a Hardcore character.
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.
Find all of the Shaper's Memory Fragments.
Tag each waypoint.
Create an item with six linked sockets using an Orb of Fusing.
Fully clear the Colosseum end-game Map.
Have 9 Raised Zombies alive at one time.
Reach level 70 as a Hardcore character.
Corrupt a skill gem into a Vaal skill gem.
Kill Abaxoth, The End of All That Is.
Complete all of the yellow maps on the Atlas.
Corrupt a Unique Jewel into a different Unique Jewel.
Have 60 Minions at the same time.
Finish Merciless Labyrinth in a Hardcore League.
Reach level 80 as a Hardcore character.
Create a Unique item using an Orb of Chance.
Craft a Jewel with four mods using an Orb of Alchemy.
Reach level 90 as a Hardcore character.
Kill the Shaper.
Corrupt a map into a Vaal Temple map.
Defeat the Pale Council.
Capture a flag during any CTF match.
Listen to all optional NPC dialogue.
Discover all environmental lore.
Reserve 95% or more of your Life.
Complete all of the red maps on the Atlas.
Have 15 combined Endurance, Frenzy, and Power Charges active simultaneously.
Complete the Hall of Grandmasters.
Kill all Warbands leaders.
Kill Atziri in the Alluring Abyss.
Kill a monster that is under the influence of five Essence mods.
Complete every map on the Atlas.
Kill every Breachlord.
Level 7 Forsaken Masters to their maximum level.
Fully upgrade every god power.
Equip each Maraketh Weapon type.