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