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