The story being non-existent? Implying there was a solid story in L4D1?
When did I imply there was a solid story in L4D1? This is part of the problem I'm talking about. No story, no intricate gameplay, maximum repetition.
It's really more about the versus aspect, the competitive nature that drives the enjoyment for me. L4D2 is still my favorite Valve game
A game should never resort using the human element as an excuse for the story being non-existant and having overly simple super-repetitive gameplay in every level. L4D [and L4D2 were] stand-alone full-price games, not versus-only-oriented $20 Orange Box components.
Also some people bought into the series based on the developer saying it was fundementally a co-op "survivor-experience".