Here is the full list of all 66 Torchlight achievements. It takes around 100-120 hours to unlock all of the achievements on Windows.
Find the entrance to the mine
Change your pet by feeding it fish
Catch 1000 fish
Die 500 times
Retire over 300 levels worth of characters
Defeat Ordrak on Hard Hardcore
Complete 50 Hatch Quests
Defeat Ordrak on Normal Hardcore
Defeat Ordrak on Very Hard Hardcore
Sell 10,000 items to vendors
Defeat Ordrak with no deaths
Defeat Ordrak on Easy Hardcore
Kill 25 champion trolls
Retire two characters
Drink 5,000 potions
Defeat Ordrak on Very Hard
Defeat Ordrak in 8 hours or less
Defeat Ordrak in less than 5 hours
5 mods installed at the same time
10 mods used at the same time
Beat the game with all three classes
Retire a character
Kill 50,000 monsters
Reach level 100
Suffer 20 disenchants from the enchanter
Achieve player level 100
Gamble 100 times
Achieved enlightenment by speaking with the horse 100 times
Gamble 50 times
Gamble 20 times
Gamble a unique item
Complete 200 Quests
Reach the 50th floor of a dungeon
Achieve maximum fame
Successfully enchant one item 10 times
Achieve player level 65
1 game mod installed
Complete 25 Gar Quests
Have 100,000 gold in your inventory
Do at least 10,000 damage to an enemy in a single strike
Catch 100 fish
Smash 1500 Breakables
Transform your pet into a Mimic
Defeat Ordrak on Easy or Normal
Defeat Ordrak on Hard
Defeat Alric
Defeat Medea
Successfully create 25 items using the transmuter
Collect 250,000 gold
Catch 50 fish
Defeat Krag
Successfully enchant one item 5 times
Have an item disenchanted on the first enchantment attempt
Take 25,000 steps
Kill 5000 Monsters
Defeat the Ember Colossus
Equip a spell on your pet
Defeat the Root Golem
Pull 100 levers
Permanently transform your pet
Defeat the Overseer
Use 50 potions on your pet
Send your pet to town
Fill your pet's inventory
Blow 25 enemies to pieces with critical strikes
Defeat Brink