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