Full list of all 80 Borderlands achievements. It takes around 50-60 hours to unlock all of the achievements in the base game on Windows.
The base game contains 50 achievements, and there are 4 DLC packs containing 30 achievements.
Completed the "House of the Ned" mission
Completed the "Jakobs Fodder" mission
Killed Ned...sort of
Killed Ned. Again.
Completed the "Braaaaaaaaaaaaains!" mission
Completed the Prove Yourself mission
Reached the end of the larger challenge in the Hell-Burbia coliseum
Reached the end of the larger challenge in The Angelic Ruins coliseum
Reached the end of the larger challenge in The Gully coliseum
Reached the end of each of the 3 larger challenges with one character
Built the New Car: Monster
Rescued Athena
Destroyed the Lance Depot
Killed Crawmerax the Invincible
Killed each of the loot midgets
Destroyed a Lancer while in a Racer
Reached Level 51
Reached Level 61
Completed all missions in Secret Armory
Paid for a worthless tour of the world's largest bullet
Read all 6 claptrap statue placards
Knoxx is at rest...finally
The Commandant is dead-trap
Killed Ned... again and again and again
Defeated the Interplanetary Ninja Assassin Claptrap
Completed Tannis' crazy request
Collected 5 3D glasses
Found 25 claptrap oil cans
Collected 15 claptrap bobbleheads
Collected 3 panties, 5 fish in a bag, and 15 pizzas