S.S.D.D.

S.S.D.D is the first level in Call of Duty: Modern Warfare 2. It serves as a tutorial to teach players basic gameplay mechanics.

Walkthrough
The level starts with Pfc. Joseph Allen and Sgt. Foley training the local milita. Sgt Foley tells Allen to do a quick weapons demostration. Allen picks up a M4A1 and shoots the targets and then tosses some frag grenades. After teaching the milita, Foley tells Allen to meet Cpl. Dunn at The Pit. Dunn demostrates that swiching to your sidearm is faster than reloding. Then Dunn tells you to run the course. In the course, you have to clear enemy emplacements and then clearing out a building without civilian casualties. After running The Pit, you choose the difficulty. Shortly after leaving The Pit, soldiers will pick up the fallen ones while more run to the stations. Thats when you get ready for battle. At the end of the mission, the Rangers will start talking about Soap MacTavish, Gary "Roach" Sanderson, and Ghost's obstacle course score.

Trivia

 * S.S.D.D means "Same Shit, Different Day" Derived from Stephen King's book, "Dreamcatcher". This goes along the lines of F.N.G. meaning " Fucking New Guy " in Call of Duty 4 Modern Warfare.
 * Pvt. Roycewicz can be found in this mission after your demostration at the firing range, mingling with the other Army Rangers. This is odd, as in Call of Duty 4 Modern Warefare, Roycewicz was assigned to Marine Force Recon.