This topic has been brought up multiple times in the comment section, so I decided to create it in the discussions for everyone, who is interested.

This campaign will remain for L4D1 Survivors by default and my decision on this is final. This is how Leafo made it. Besides, we got another Silent Hill campaign by Leafo (Which is Otherside of Life) with L4D2 survivors.

However, it is still possible to have L4D2 Survivors in this version by creating a simple Survivor Swap mod. You will need to learn how to create mods. Extract the mission file from this campaign, and change the survivor_set to 2. Make sure the survivor swap is above the campaign in addonlist.txt. Everyone will need to install it, otherwise those who don't will have l4d1 survivors hands in the firstperson view. If you have Source Mod installed on your server, this is not needed, because you can use admin menu to change anyone's survivor to whatever you want.