My sister and I sold our PS4 awhile back and have been keeping an eye out for PC co-op games, during Black Friday sales we brought Left4Dead and sequel cheaply. Heard good things, would allow us to test how co-oping from different computers would work for us. Had a great time yesterday with the first Left4Dead camapign and looking forward to the next one (we calculate one camapign at a time to prevent burnout).
Wasn't quite what we expected, we had to adjust our tactics (like shut doors behind) and go onto easy as we aren't good at it simply to get through first chapter. For a game that is ten years old, it holds up well (though a "RUUUUUN" button would have been nice), controls solid, varying where items and some zombie attacks happen prevents things getting samey if you fail level then come back. Some nice touches to prevent accidental leaving people behind and trapping them, suitably creepy music at right times, the odd setplay to keep things fresh.
The AI supporting 2 we had in group of four was extremely well balanced in they weren't super-powered or inept but reliable support who would heal up and react to events, was glad to have them without feeling shown up. Found their scores always tended to be in the middle. Not always keeping with the character you picked is a minor irritant, could be more helpful in where you need to go but we enjoyed pushing on, tension when hordes seemed set to overwhelm us, cursing when bloater got our face covered and couldn't see what I was shooting.
We love the film touch, the poster at the start with our steam names for starring as, the humorous film credits at the end of the campaign. The safe house between chapters also brings some much needed humanity as you observe the scrawled messages on the walls from people who had been there before, some emotional, some amusing.