Here is the full list of all 119 Torchlight II achievements. It takes around 200 hours to unlock all of the achievements on Windows.
Join a multiplayer game
Start a multiplayer game
Destroy 10 socketed gems
Find 100 secret rooms
Break 10,000 breakables
Use 5,000 potions
Destroy a socketed gem
Wear a completed armor set
Reach level 100
Find a legendary item
Defeat Verona
Defeat Aleera
Defeat Marishka
Assemble TrillBot
Sell 5,000 items
Defeat Boletus Rex
Obtain a tier 3 skill bonus
Defeat 500 champions
Begin new game plus
Squish 1000 critters
Recover 100 gems from items
Use an enchanter 500 times
Die with a hardcore character
Start a hardcore character
Deal 10,000 critical strikes
Use 10 maps
Teach a pet 4 spells
Purchase 100 items from the gambler
Purchase 50 items from the gambler
Have 10,000,000 gold
Purchase 20 items from the gambler
Socket 50 gems into items
Explode 10,000 enemies
Find 10 secret rooms
Squish 500 critters
Add a friend
Use a map
Take 100,000 steps
Have 1,000,000 gold
Have 100,000 gold
Fish 100 times
Defeat the Nether King in Casual difficulty
Defeat the Nether King as an Outlander
Defeat the Nether King
Recover 10 gems from items
Defeat the Dark Alchemist
Break 1,000 breakables
Defeat One-Eyed Willy
Defeat Mordrox
Defeat Vyrax
Defeat Killbot
Defeat Thiss
Use an enchanter 50 times
Defeat Cacklespit
Do 10,000 damage with a single attack
Defeat Bloatfang
Defeat the Wraith Lord
Defeat the Grizzled Alpha
Obtain a tier 2 skill bonus
Open 500 chests
Fish using dynamite
Take 50,000 steps
Recover a gem from an item
Defeat 100 champions
Defeat the Siege Guardian
Defeat Ezrek Khan
Use 500 potions
Defeat Aruk
Defeat the King In Masks
Teach a pet a spell
Sell 500 items
Squish 100 critters
Defeat Chillhoof
Defeat the Fallen Guardian
Socket a gem into an item
Learn 4 spells
Defeat the Artificer
Deal 1,000 critical strikes
Defeat the Manticore's Mate
Defeat the Manticore
Explode 1,000 enemies
Use an enchanter 10 times
Defeat Grand Regent Eldrayn
Fish 10 times
Learn a spell
Open 100 chests
Defeat King Pogg
Take 10,000 steps
Defeat 25 champions
Defeat Kidrik the Mauler
Use 50 potions
Defeat the Winter Widow
Obtain a tier 1 skill bonus
Defeat General Grell
Break 100 breakables
Find a secret room
Send your pet to town
Explode 100 enemies
Open 20 chests
Defeat the Nether King with each of the 4 classes
Defeat the Nether King as a Berserker
Defeat the Nether King in Elite difficulty
Defeat the Nether King in Normal difficulty
Defeat the Nether King in Veteran difficulty
Defeat the Nether King as an Embermage
Defeat the Nether King as an Engineer
Defeat the Nether King in hardcore mode (casual)
Defeat the Nether King in hardcore mode (elite)
Defeat the Nether King in hardcore mode (normal)
Defeat the Nether King in hardcore mode (veteran)
Deal 100,000 critical strikes
Fish 1,000 times
Have 10 friends
Have 50 friends
Destroy 100 socketed gems
Sell 50,000 items
Socket 500 gems into items
Trade an item with another player
Use 100 maps