This achievement is for completing the thirteenth mission of the game and can be obtained on any difficulty.
Here's my playthrough of Mission 13 Bunker Buster on normal.
Aircraft used: F-22A
Special weapon: TGTP (Bunker Busting Bomb - automatically selected)
Score required: None
Time limit: First section 10:00 / second section 10:00 - although in practice you go from one IRBM to the next in this part (Normal)
The objective for the first section is to destroy the 8 missile silos using the TGTP bunker buster. Not all of the silos are real.
The second section sees you shooting down 3 IRBM missiles. Get to them as quickly as you can, shoot your missiles and then use guns while waiting to reload. The IRBM's are slow to start with but when they pick up speed you will lose them very fast. Don't waste any time, shoot everything you have at them as quickly as you can. It takes approximately 3 missiles per IRBM or 2 missiles and a few rounds from the guns.Tip: I played through a couple of hours of multiplayer, gaining enough MRP (in game currency) to purchase the F-15E which made this a lot easier and more fun than the starting F-16C. Around Mission 12, I had enough to purchase the F-22A which is the most capable aircraft I've found so far. The currency, planes and most part upgrade unlocks work across multiplayer / singleplayer but some upgrades are exclusive to multiplayer. You can also go into 'Free Mission' to replay for some extra cash.