I love 2D remakes, so I was stoked when I found a video about L4D in 2D. It's always so fun to see aspects of the game you know so well in 3D torn back through time into an era of Player Select screens and whatnot. The coolest part about it is definitely how well it syncs up to the No Mercy campaign. Every scene is more or less the exact same as the stage in the 3D version. Obviously the gameplay is different....really different; you don't really have to worry about zombies bursting out of walls or corners, and there's no AI director. The most disappointing part about it is that there aren't all the special infected, but I can see how that would be hard, especially since it's one player and what do you do if a Hunter has you pinned all by yourself?
It looks like they finished the game so I'll give it a looksee and see if there are any more elements added. Just think of the video as a taste.