HaloRadar: Guide to Every Skull

Mission: Floodgate

Effect: Say goodbye to your motion sensing radar.

Instructions:At the start of the mission, as you head away from the hill and into the base, Flood zombies will leap from one rooftop to another. Snipe the closest one in midair and the skull will drop onto the ground. Don't kill it on either rooftop or the skull will remain out of reach. Definitely takes a few attempts, but playing on normal difficulty helps.