Rooftops is a wide map made, probably, especially for the Hammer of Dawn. There are two Hammer of Dawns, two Longshot Sniper Rifles, and two frag grenade spawns. In the center, there is the Torque Bow. This map has little cover, allowing for heavy Hammer bombardment. This is one of the few maps to not feature a Boomshot Grenade Launcher.
This is one of the Hammer of Dawn's best maps. The central corridor is largely uncovered, and since it's the only way to get from one side of the map to the other, it's also highly populated. Sweep over the corridor with fire from the Hammer of Dawn. If you're trying to avoid the Hammer, look for short protrudings overhead that provide just enough cover. This map's Torque Bow is also very effective, as the range makes the user's arrow hard to see. Also, each side of the map provides access to one of two dugout areas, small rooms with openings just large enough to let through gunfire. Enemies often camp in these dugouts while firing with the Hammer of Dawn and Torque Bow weapons. And while the dugout inhabitant may think himself clever, he's very vulnerable to frag grenades. Toss in a frag for a quick and easy kill.
The easter egg on Rooftops is of a dead body sitting on a toilet. After spawning on a side of the map (Note: this easter egg is only on one side of the map) proceed over to where you would get the Hammer of Dawn and the Longshot. You could either take the Hammer of Dawn and use it or use a Smoke Grenade. To use the Hammer of Dawn, a method that supplies a better view of the Easter egg, aim it to the building directly opposite of the room where you acquire the Hammer of Dawn. Fire it into the windows until you finally see it. To use a smoke grenade, it is much easier. Simply toss the smoke grenade into the correct window and you will see it as only a black figure.