3: In the Crosshairs

Grand Theft Auto 4: The Ballad of Gay Tony Guide - Walkthrough

Bulgarin's Missions - 3: In the Crosshairs

You'll want to buy some Body Armor before setting out on this one. Grenades and RPG ammo too if you have the cash. Also, if you haven't yet completed the last mission in Yusuf's mission line (“For the Man Who Has Everything”), do that first to get extra explosive rounds for your Explosive Shotgun. Hit the marker outside of Bulgarin's house when you're ready to get started.

Make your way to the marker in Little Italy, Algonquin, to travel up to the top of the building. Following the cutscene a number of snipers will have you in their sights. You're armed with an Advanced Sniper, but you're also severely outnumbered. There are snipers all over surrounding rooftops; you need only kill four of them.

Each time a sniper takes a shot, he will appear on your radar as a red blip for a few seconds.

Sniper vs. snipers!

You must find some way back to street level. Start by walking around to the south side of the roof. Look southwest for a sniper on the building, take aim with your rifle, and shoot him when he pops up. Then, take out the sniper on top of the high building with the green trim to the north. Once that sniper is down, jump over the railing along the west side of the building to the lower rooftop.

Climb up the wall to the west and take cover behind the small structure there. Look west and take out the sniper on the building that has a water tank on top of it. Then, move to the southeast corner of the rooftop and look southeast for a sniper perched on the building there. Kill the fourth sniper to trigger a wave of enemies.

Completing 4 shots, 4 snipers

When the gunship appears, use your Explosive Shotgun or RPG Launcher to shoot it down. Take another look at the red building with the water tank for more snipers; there should be another sniper there.

If you brought Grenades along with you, throw one or two at the enemies further west along the rooftops. Hold on to the grenade for a few seconds after pulling the pin by holding RT; doing so will give the enemies less time to react before it goes off. The enemies at this portion seem to spawn indefinitely, so clear the way and then quickly move further along the rooftop.

Toss a grenade to take out the enemies along your escape route.

There's an enemy armed with what appears to be a Grenade Launcher on the building where the third sniper was, so if you see him fire his weapon, either quickly fallback or run forward to avoid getting caught in the blast.
 
Continue heading west when the way is clear and grab the vest of Body Armor along the way. When you reach the water tower, take out the enemy on the building across the street to the west as well as the one below before dropping down to the lower rooftop. Then, make your way to the marked fire-escape and climb down to street level. Steal a car and flee the scene to complete the mission.

Secondary Objectives
Time: 0:04:30
Player Damage: 40%
Headshots: 10
Accuracy: 60%
4 shots, 4 snipers