1: The art of dodging bullets - usually in a video game, however the term can be applied to real life.
2: A combination of regular stance and prone position and/or zig-zag in order to avoid projectiles.
3: A strategy to make oneself hard to hit by snipers.
Chris: What the heck, I emptied a whole clip in that guy, how did I not hit him?
Bob: Yeah, that cat got mad dip-game.
Matt: Those who practice Ninjutsu are taught to read the trajectory of a bullet in close quarters and move a defensive attack accordingly. Thus, they sorta have dip-game.