Here is the full list of all 27 Call of Duty: Modern Warfare achievements.
Complete all Special Operations missions.
Kill all enemies at the Church, Clocktower, and Pool without anyone calling for backup.
Complete 'The Wolf's Den' tunnels using only the 1911.
Kill an enemy with a direct hit from a smoke grenade.
Complete 'Clean House' without being hit using one bullet per threat.
Burn 4 enemies with a single molotov.
Kill all the enemies in the 'Embedded' field of dead bodies.
Kill at least one enemy while inside The Reading Place, Aural Chic, and both Subway undergrounds.
Neutralize the 'Fog of War' machine gun with a frag grenade.
Complete every single player mission on Veteran or Realism difficulty.
Reach Barkov's lab entrance using only drone strikes.
Shut off the power to 4 buildings in 'Going Dark'.
Get at least one kill with eight different weapons when completing 'Old Comrades'.
Never get hit by the sniper while escaping captivity.
Spit on Barkov.
Kill 3 enemies while you are on a ladder.
Kill both soldiers with one shot in 'Hometown'.
Destroy 4 trucks with 4 drone strikes before they reach the end of their path in 'The Embassy'.
Save Alpha 3-2 from being downed.
Take down a flying helicopter with a molotov.
Crash a helicopter by shooting the pilot.
Only use one cinder block and bring it to the end of 'Embedded'.
Finish single player on any difficulty.
Blow up 3 tripwires with explosives.
Stop three APCs with Hadir's sniper rifle.
Shoot the driver of the suicide truck.
Do not injure any civilians in 'Piccadilly'.