Call of Duty: Modern Warfare 2/Bomb Squad

Walkthrough
The last thing to do is split up with your partner. Unless you're both very skilled players and don't die easily, stick with your partner. You have enough time to defuse all of the bombs together, and it's safer that way.

The first bomb should be all the way to the right. Choose any gun you're comfortable with and head there, but have your gun ready. You have to shoot through the people in your way, but take your time. With two people, it should be easier. Most of them will be on the ground, but some will be running along the rooftops. Shoot them before they can take position. Keep going through an even thinner alleyway and after defusing the bomb, run back to get to the other two. For the next two, you have to head all the way to your starting point and go all the way on the left this time.

Find some cover, aim, and shoot. After the people in this area are out of your way, head in the house. There, the bomb should be defused, but somebody should stay on the lookout. Enemies can come surprisingly quickly up behind you. Now head out of the house to reach the last bomb. A lot of enemies will be guarding the last bomb, but whatever you do, don't just run passed them and assume you can defuse the bomb before you can die. Shoot through most of the enemies before another wave can come and defuse the bomb while somebody watches your backs again, and your mission will be cleared.