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