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