cura on 27 January 2014
If they are developing l4D3, I don't think including L4D2 maps would be a priority at this stage.
I think it's probably L4D2 maps done with the source 2.0 engine although I could be wrong.
Also, those screenshots have an 'amateurish' feel about them... It's not how I would have thought L4D2 would look in source 2.0...
