Here is the full list of all 50 Battlefield: Bad Company achievements worth 1,000 gamerscore.
Completed 'Ghost Town' on hard
Completed 'Crash and Grab' on hard
Found half of the gold bars
Completed 'Air Force One' on hard
Completed 'Par for the Course' on hard
Completed 'Crossing Over' on hard
Completed 'Acta Non Verba' on hard
Completed 'Welcome To Bad Company' on hard
Completed 'Ghost Town' on normal
Completed 'Crash and Grab' on normal
Climbed to the highest spot in the game
Completed one mission without dying (any difficulty)
Completed 'Air Force One' on normal
Killed 25 enemies in a helicopter
Drove all vehicle types (Jeep, Tank, Heli, Boat)
Completed 'Par for the Course' on normal
Destroyed 50 vehicles. (containing enemy AI)
Found half of all collectables
Completed 'Crossing Over' on normal
Completed 'Acta Non Verba' on normal
Destroyed 200 Walls
Found 5 unique collectables
Used auto Injector 50 Times
Found one gold bar
Completed 'Welcome To Bad Company' on normal
Knocked down a small forest
Killed 25 enemies
Hit hostile helicopter with laser designator
Find all collectables
Find all gold bars
(Online) Participate in one online match (Ranked)
(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) Take 3 pictures using the image system
(Online) Glide in the parachute for 3 seconds
(Online) Achieve all the awards
(Online) Achieve half of all awards
(Online) Get 10002 kills