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