Unlock the following stamps by performing the corresponding tasks:
STAMP - HOW TO UNLOCK Knife Efficiency - Kill four players with melee weapons. Explosives Efficiency - Kill four enemies with grenades or explosives. AT Efficiency - Kill four vehicles with the recoilless rifle. Rifle Grenade Efficiency - Kill four enemies with rifle grenades. Pistol Efficiency - Kill four enemies with the pistol. Rifle Efficiency - Kill four enemies with the semi-automatic rifle. SMG Efficiency - Kill four enemies with the submachine gun. Sniper Efficiency - Kill four enemies with the scoped rifle. Vehicle Efficiency - Destroy six vehicles in any fashion. Jeep Efficiency - Get four kills with a car. Tank Efficiency - Get four kills with a tank. Plane Efficiency - Get five kills with a fighter plane. Boat Efficiency - Get two kills with a landing craft. HMG Efficiency - Get four kills with a heavy machine gun. Air Defense Efficiency - Kill two planes with an anti aircraft gun. Bombing Efficiency - Kill four enemies with air raids. Air Superiority - Shoot down three bombers. Vehicle Assist Efficiency - Get five vehicle assist kills. Leatherneck - Kill 20 enemies. Defender Efficiency - Defend five flags. Attacker Efficiency - Capture five enemy flags. Best Squad - Be the best squad of the round. Teamplayer - Get 10 squad assists. Squad Excellence - Each squad member gets any one stamp and kills 10 enemies.