nope "We've added 'Onslaught' mode, which introduces an AI Director that dynamically generates swarms of aliens based on several factors, such as the squad's stress level," explains Valve. "Onslaught works with any difficulty setting and ensures no mission plays the same way twice."
Additionally, a difficulty setting has been added above "Insane", called "Brutal". "How brutal is Brutal? Nobody on the Alien Swarm team has managed to complete a mission on it." Ouch!
Another modifier, "Hardcore Friendly Fire", means that "friendly fire deals full damage immediately, flamethrowers set teammates on fire much faster, and turrets will hurt you if get caught in their crossfire."
To go along with all these new modes and challenges, three additional IAF Promotion Ranks have been added: Platinum Star, Osmium Star, and Iridium Medallion.
Players should automatically receive the update after launching Steam.
[Thanks, The Grolar Bear]