Here is the full list of all 50 Cobalt achievements worth 1,000 gamerscore.
Destroy one Radio
Beat a combat challenge with 100% accuracy and 100% health
Complete combat challenge by only eliminating the targets
Beat a combat challenge without firing a weapon or throwable
Dodge ten homing missiles without dying
Reach level 10 dance
Dance to the tune of a radio playing music
Protect Bopo in Survival
Buy one Upgrade
Win TS-match without dying
Complete survival wave without firing a weapon or throwing a grenade
Finish survival round as brain
Win a deathmatch without dying a single time
Win one round of Team-Strike with whole team surviving
Win two Team-Strike rounds in a row without dying
Kill an enemy with a punch to the head while rolling in the air
Wiped the entire opposing team in Team-Strike
Complete a speed challenge under mountainhammer time
Complete a speed challenge under par time
Kill enemy with klonk
Kill two enemies at once
Kill two enemies with one bullet
Boost one reload
Perfectly deflect a scoped bullet
Kill an enemy with a scoped bullet
Dodge a homing missile
Free one prisoner
Rescue all prisoners in a combat challenge without them recieving any damage
Kill one enemy using physics
Kill an enemy with a deflected bullet
Kill an enemy while rolling
Hack one Computer
Blind one enemy with one flashbang
Lockpick one door
Kill an enemy with your feet
Kill two enemies without touching the ground
Kill an enemy with a kicked grenade
Mine one block
Find one secret
Crack one Safe
Perfectly deflect a bullet
Kill an enemy with a Boomerang boosted by a Force Device
Heal two players with one nano dispenser
Tame a Sabretooth Hamster
Complete all combat challenge maps
Unlock all unlocks
Complete all speed challenge maps
Kill an enemy with a punched grenade
Complete survival game without dying
Complete all brain challenge maps under mountainhammer time