Here is the full list of all 50 Battlefield: Bad Company achievements worth 1,000 gamerscore.
Completed 'Welcome To Bad Company' on hard
Found 5 unique collectables
Killed 25 enemies
Used auto Injector 50 Times
Found one gold bar
Achieved half of all awards
Found all gold bars
Got at least one kill in every vehicle
Found all collectables
Reached Rank 25
Collected 50 unique dog tags
Reached Rank 20
Knocked down 1000 trees
100 kills using vehicle
Collected 5 unique dog tags
Played 100 online matches
Completed 'Ghost Town' on normal
Completed 'Crash and Grab' on normal
Completed 'Air Force One' on normal
Took 3 pictures using the image system
Destroyed 1000 walls
Used Squad in the menu, found a friend and played one round
Completed 'Par for the Course' on normal
Completed 'Crossing Over' on normal
Completed 'Acta Non Verba' on normal
Completed 'Welcome To Bad Company' on normal
Reached Rank 8
There is no parachute, right?
Placed #1 in a Ranked Match
Reached Rank 3
Played one complete ranked online match
Completed one mission without dying (any difficulty)
Completed 'Ghost Town' on hard
Hit hostile helicopter with laser designator
Found half of the gold bars
Completed 'Crash and Grab' on hard
Climbed to the highest spot in the game
Completed 'Air Force One' on hard
Killed 25 enemies in a helicopter
Destroyed 50 vehicles. (containing enemy AI)
Drove all vehicle types (Jeep, Tank, Heli, Boat)
Completed 'Par for the Course' on hard
Knocked down a small forest
Found half of all collectables
Completed 'Crossing Over' on hard
Completed 'Acta Non Verba' on hard
Destroyed 200 Walls
(Online) Have 20 Squad members spawn on you without dying in a single round
(Online) Achieve all the awards
(Online) Get 10002 kills