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.
Killed 15 enemies with the Hunter's action skill
Rescued enough Claptraps to earn 42 inventory slots
Completed all missions in the Rust Commons
Killed 15 enemies with the Soldier's action skill
Completed all missions in the Arid Badlands
Killed the Vault Boss
Earned $1,000,000
Killed Flynt
Emerged victorious from an arena match
Raced around the Ludicrous Speedway in record time
I bet you never thought you'd be here.
Killed 5 Rakk in under 10 seconds
Killed Krom
Killed 25 enemies with explosive weapons
Mastered the technology of Pandora
Killed an enemy plumber-style
Completed 5 missions in the Rust Commons
Killed 25 enemies with corrosive weapons
Equipped a class mod for your character
Killed Sledge
Killed 25 enemies by ramming them with any vehicle
Killed an enemy with the Siren's action skill
Sold 50 guns to a shop
Applied an elemental artifact
Killed 25 enemies with shock weapons
Killed 25 enemies with incendiary weapons
Won a duel without taking damage
Completed 15 missions in co-op
Won a duel against another player
Rescued a groupmate from death in a co-op game
Killed 15 enemies with the Berserker's action skill
Completed 5 missions in the Arid Badlands
Gamed with fame
Discovered The Scrapyard
Discovered Crimson Lance Enclave
Discovered Headstone Mine
Discovered Eridian Promontory
Discovered Sledge's Safe House
Discovered Skag Gully
Earned level 50
Earned level 40
Earned level 30
Earned level 20
Reached proficiency level 10 with any weapon type
Defeated the Rakk Hive, the Vault Boss, Sledge, Krom, or Flynt in a co-op game
Killed the Rakk Hive
Earned level 10
Earned level 5
Discovered Trash Coast
Discovered Krom's Canyon
Complete the "House of the Ned" mission
Complete the "Jakobs Fodder" mission
Kill Ned
Actually kill Ned
Complete the "Braaaaaaaaaaaaains!" 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
Reached Level 61
Rescued Athena
Destroyed a Lancer while in a Racer
Built the New Car: Monster
Killed Crawmerax the Invincible
Destroy the Lance Depot
Kill each of the loot midgets
Complete all missions in Secret Armory
Pay for a worthless tour of the world's largest bullet
Reached Level 51
Find all 6 Claptrap Statues
Kill General Knoxx-Trap
Kill Commandant Steele-Trap
Kill Dr. Ned-Trap
Kill the INAC
Complete a crazy request for Tannis
Find 25 oil cans
Collect 15 claptrap bobbleheads
Collect 5 3D glasses
Collect 3 panties, 5 fish in a bag, and 15 pizzas