ACHIEVEMENT - HOW TO UNLOCK Battle-hardened - Complete all single player levels 1-5. Elite Unit - Complete all single player levels 1-5 on Elite difficulty. Exterminator - Kill 1000 aliens in single player. Frag-master - Kill 10 aliens with one frag grenade. Hidden Treasure - Find all secret collectibles. Immobilised - Stun 10 aliens with one stun grenade. Meat Grinder - Kill 250 aliens on any multiplayer Survivor level. More Speed, Less Haste - Complete 'Vengeance' single player level on Veteran difficulty in 17 minutes or less. Seasoned Squaddie - Complete any multiplayer level. Survivor - Stay alive for 8 minutes on any single player Survivor level. Tank - Take 500 damage on 'Determination' single player mission without dying. The Informed - Collect all the logs throughout the game. Time to Party - Complete 3 Co-op Assault multiplayer games.