Full list of all 80 Borderlands achievements worth 1,750 gamerscore. It takes around 40-50 hours to unlock all of the achievements in the base game on Xbox 360.
The base game contains 50 achievements worth 1,000 Gamerscore, and there are 5 DLC packs containing 30 achievements worth 750 Gamerscore.
Raced around the Ludicrous Speedway in record time
Earned level 50
I bet you never thought you'd be here.
Completed all missions in the Rust Commons
Rescued enough Claptraps to earn 42 inventory slots
Earned level 40
Killed the Vault Boss
Discovered Eridian Promontory
Discovered Crimson Lance Enclave
Killed an enemy with the Siren's action skill
Killed 15 enemies with the Hunter's action skill
Killed Flynt
Killed the Rakk Hive
Discovered Trash Coast
Killed Krom
Earned level 30
Discovered Krom's Canyon
Completed 5 missions in the Rust Commons
Discovered The Scrapyard
Completed all missions in the Arid Badlands
Killed 25 enemies with corrosive weapons
Sold 50 guns to a shop
Applied an elemental artifact
Killed 5 Rakk in under 10 seconds
Killed 25 enemies with explosive weapons
Killed 25 enemies by ramming them with any vehicle
Killed 15 enemies with the Berserker's action skill
Rescued a groupmate from death in a co-op game
Equipped a class mod for your character
Defeated the Rakk Hive, the Vault Boss, Sledge, Krom, or Flynt in a co-op game
Killed Sledge
Discovered Headstone Mine
Mastered the technology of Pandora
Discovered Sledge's Safe House
Killed an enemy plumber-style
Killed 25 enemies with shock weapons
Completed 15 missions in co-op
Reached proficiency level 10 with any weapon type
Earned level 20
Earned $1,000,000
Killed 25 enemies with incendiary weapons
Killed 15 enemies with the Soldier's action skill
Discovered Skag Gully
Completed 5 missions in the Arid Badlands
Earned level 10
Earned level 5
Gamed with fame
Win an arena match
Win a duel against another player
Win a duel without taking damage
Completed the "Braaaaaaaaaaaaains!" mission
Killed Ned. Again.
Killed Ned...sort of
Completed the "Jakobs Fodder" mission
Completed the "House of the Ned" mission
Complete the Prove Yourself mission
Reach the end of the larger challenge in the Hell-Burbia coliseum
Reach the end of the larger challenge in The Angelic Ruins coliseum
Reach the end of the larger challenge in The Gully coliseum
Reach the end of each of the 3 larger challenges with one character
Completed all missions in Secret Armory
Killed Crawmerax the Invincible
Reached Level 61
Paid for a worthless tour of the world's largest bullet
Destroyed the Lance Depot
Killed each of the loot midgets
Rescued Athena
Destroyed a Lancer while in a Racer
Built the New Car: Monster
Reached Level 51
Read all 6 Claptrap statue placards
Defeated the Interplanetary Ninja Assassin Claptrap
Completed Tannis' crazy request
Collected 5 3D glasses
The Commandant is dead-trap
Killed Ned...again and again and again
Knoxx is at rest...finally
Find 25 oil cans
Collect 15 claptrap bobbleheads
Collect 3 panties, 5 fish in a bag, and 15 pizzas