The Reduction Title update for Alien Swarm: Reactive Drop has 12 achievements.
Complete the Reduction campaign on Easy difficulty or harder.
Complete the Reduction campaign on Normal difficulty or harder.
Complete the Reduction campaign on Hard difficulty or harder.
Complete the Reduction campaign on Insane difficulty or harder.
Complete the Reduction campaign on Brutal difficulty.
Complete Silent Station within 4:40 on Normal difficulty or harder without any marines dying.
Complete Operation Sandstorm within 3:00 on Normal difficulty or harder without any marines dying.
Complete Fallen City within 1:38 on Normal difficulty or harder without any marines dying.
Complete Stowaway within 1:15 on Normal difficulty or harder without any marines dying.
Complete Inevitable Escalation within 6:00 on Normal difficulty or harder without any marines dying.
Complete Nuclear Escort within 4:44 on Normal difficulty or harder without any marines dying.
Complete the Reduction campaign on Normal difficulty or harder without any marines dying.