Here is the full list of all 50 Battlefield: Bad Company achievements worth 1,000 gamerscore.
Played one complete ranked online match
Took 3 pictures using the image system
Completed 'Ghost Town' on normal
Hit hostile helicopter with laser designator
Found all collectables
Completed 'Crash and Grab' on normal
Found all gold bars
Climbed to the highest spot in the game
Completed 'Air Force One' on normal
Completed 'Par for the Course' on normal
Completed 'Crossing Over' on normal
Found half of the gold bars
Completed 'Acta Non Verba' on normal
Completed one mission without dying (any difficulty)
Completed 'Welcome To Bad Company' on normal
Completed 'Ghost Town' on hard
Completed 'Crash and Grab' on hard
Completed 'Air Force One' on hard
Killed 25 enemies in a helicopter
Completed 'Crossing Over' on hard
Destroyed 50 vehicles. (containing enemy AI)
Drove all vehicle types (Jeep, Tank, Heli, Boat)
Completed 'Par for the Course' on hard
Found half of all collectables
Knocked down a small forest
Found 5 unique collectables
Completed 'Acta Non Verba' on hard
Used auto Injector 50 Times
Destroyed 200 Walls
Found one gold bar
Completed 'Welcome To Bad Company' on hard
Killed 25 enemies
(Online) Play 100 online matches
(Online) Destroy 1000 walls
(Online) Knock down 1000 trees
(Online) Use Squad in the menu, find a friend and play one round
(Online) Have 20 Squad members spawn on you without dying in a single round
(Online) Collect 5 unique dog tags
(Online) Collect 50 unique dog tags
(Online) Place #1 in a ranked match
(Online) Get at least one kill in every vehicle
(Online) Reach Rank 3
(Online) Reach Rank 8
(Online) Reach Rank 20
(Online) Reach Rank 25
(Online) 100 kills using vehicle
(Online) Glide in the parachute for 3 seconds
(Online) Achieve all the awards
(Online) Achieve half of all awards
(Online) Get 10002 kills