This is the First Covert Operation in-game.
The player is restricted to Rambro-only at start. However other Bros can be featured when playing with other players.
Look for Crates that have the American Flag on them. Those are Ammo Crates. Break one and pick what's dropped, you will get all what you need here-special replenished.
Now you may see a large pit in front of you. Do not jump in as there's spike traps that can kill you. To bypass it, throw a Grenade down and blow the spikes up to ensure a safe jump, or return to where you started and blow up the ground there, which will make the ground collapse and you have entered the Terroist area.
This is an underground craven, infested by Terroist. Attack them from afar to prevent accidents happened to kill you. Grenades + high ground can take out Bruisers. As well as Attack Dogs, both with ease.
Once you have cleared out the majority the mooks and moving to the end of the level, there will be two drill-mook dispensers. Try to deal with that using Grenades before they give you more mooks.
At the end there will be a Mook General, just kill him and wait for your helicopter to arrive, which ends the level.