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