Here is the full list of all 50 Battlefield: Bad Company achievements worth 1,000 gamerscore.
Reached Rank 20
100 kills using vehicle
Got at least one kill in every vehicle
Completed 'Ghost Town' on hard
Found all gold bars
Found all collectables
Completed 'Crash and Grab' on hard
Destroyed 1000 walls
There is no parachute, right?
Collected 5 unique dog tags
Completed 'Air Force One' on hard
Took 3 pictures using the image system
Placed #1 in a Ranked Match
Reached Rank 8
20 Squad members spawned on you and you didn't die!
Reached Rank 3
Completed 'Par for the Course' on hard
Killed 25 enemies in a helicopter
Found half of the gold bars
Used Squad in the menu, found a friend and played one round
Played one complete ranked online match
Completed 'Crossing Over' on hard
Completed 'Acta Non Verba' on hard
Completed 'Welcome To Bad Company' on hard
Killed 25 enemies
Used auto Injector 50 Times
Completed 'Welcome To Bad Company' on normal
Found one gold bar
Completed 'Ghost Town' on normal
Hit hostile helicopter with laser designator
Completed one mission without dying (any difficulty)
Found half of all collectables
Destroyed 50 vehicles. (containing enemy AI)
Completed 'Crash and Grab' on normal
Climbed to the highest spot in the game
Completed 'Air Force One' on normal
Knocked down a small forest
Drove all vehicle types (Jeep, Tank, Heli, Boat)
Completed 'Par for the Course' on normal
Completed 'Crossing Over' on normal
Found 5 unique collectables
Completed 'Acta Non Verba' on normal
Destroyed 200 Walls
(Online) Play 100 online matches
(Online) Knock down 1000 trees
(Online) Collect 50 unique dog tags
(Online) Reach Rank 25
(Online) Achieve all the awards
(Online) Achieve half of all awards
(Online) Get 10002 kills