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