Here is the full list of all 34 Battle Group 2 achievements.
Hit 10,000 targets
Fire 10,000 missiles
Destroy 1,000 Hind helicopters
Destroy 1,000 Skyhawk planes
Destroy 1,000 Flanker planes
Destroy 500 Hind helicopters
Destroy 1,000 Suicide Boghammers
Destroy 1,000 Cruise Missiles
Destroy 500 Suicide Boghammers
Unlock 4 primary ships
Unlock 8 ships in total
Destroy 1,000 Frogfot planes
Destroy 500 Skyhawk planes
Take down 15 missiles with one EMP
Fend off The Talon once more
Destroy 500 Flanker planes
Destroy 500 Frogfoot planes
Destroy 500 Cruise Missiles
Unock 4 support ships
Earn 80 stars
Earn 50 stars
Watch the airliner fly away
Reload 3 secondaries with one Reload
Use all 3 Satelite Strikes 10 times each
Earn 30 stars
Hit 1,000 targets
Use all 3 Satelite Strikes
Unlock a new primary ship
Earn 20 stars
Fire 1,000 missiles
Fight off the Talon's submarine
Earn 10 stars
Unlock an upgrade
Unlock a support ship