Could not have been better!
Truth be told, I laughed most of the time through this flash. I absolutely loved the humour you put into it. It was great how I thought there was a break due to dancing and music, and still you manage sneaking in very short moments that force a smile on someone's face at the very least.
You did it. You used the same element over again, and despite getting old, it just felt like it got renewed and even more funny - The chicken bots (literally) reflect how many feel regarding the Survivor bots in the game during singleplayer. Heh, I have had a Witch incapacitate and kill me and the bots just stared at her! The part with the Hunter and the Space Odyssey theme was probably the part I loved the most, apart from the very start itself of the flashmovie.
I really enjoyed the way the characters and infected were drawn, and every once the Hunter was grinning was pure epic. Ending the flash with a musical touch was very fitting, I feel, especially since it did not take long before I laughed again. The credits, as the true ending, fit really well too due to ending just like a Left 4 Dead campaign, it just felt really nice.
You are a genius for combining all of this so well and making a flash out of it. It is sad to hear you have no plans on making more flashes, or on Newgrounds at least, because this is a masterpiece in my eyes. Thank you!