No, it’s not a joke, and no, we don’t really hate mountains. “I Hate Mountains” is the name of a Left 4 Dead 1 & 2 campaign made by three French friends. Be aware that this campaign is built the Valve way, we are not trying to revolutionize anything, we just want to provide more content to this awesome game. The campaign is divided into five different maps, just like Valve did with their own campaigns in Left 4 Dead 1. The difference is that ours is entirely nature-oriented, there’s only a few building and most of the action takes place in outdoor environments, which is a challenge to build in itself. We also focused our development on offering a better re-playability by providing several long alternate paths in the levels that can totally change the way you play it.
It's been a while since I played, but as I recall it was a pretty solid campaign. There were a few issues though.
The beginning area had a lot of long dead-ends, it kinda sucked to be walking and realize you've been going the wrong way, fighitng through the horde the entire time.
The sequence with the chopper was misleading, as I restarted the game once the chopper had left, thinking I had failed. The finale was pretty good, although I espected a helicopter to land, as did my friends, and we were surprised to had a plane come in.
The finale plane was clipped a bit poorly, it seemed we'd try to jump in and just fall right into the water, not a huge issue.
Overall good campaign, 9/10