Instructions
Start a multiplayer game. The turret upgrade and downgrade power ups do not appear in single player games.
Play the game as you normally would until the opposing team upgrades its turrets. Turrets receive upgrades when a player collects a power up that looks like a green turret. A driver collects the power up when he drives into it; a shooter collects it when he hits the power up with a turret shot.
Drive into or shoot a red turret power up to downgrade all the opposing team's turrets if you're a driver or shooter, respectively.