So I finally managed to play Firewatch last week, after about four months. I'd been waiting for a free day so I could sit and play through it in one go. It was well worth it, and thankfully it ran okay on my PC (on high settings).
I enjoyed it. It took me five hours, but they were five hours well spent. The story was good, and had me genuinely wondering where it was going and what was going to happen next. I felt that sense of dread that something bad was going to happen, and the tension was palpable. Sure it was linear but IMO linear stories are always the best ones so no complaints there.
The only small gripes I had were that there wasn't much consequence to your dialogue choices - I was expecting something more akin to The Walking Dead where the things you said over the radio would affect your relationship with Delilah, but that really wasn't the case. I also didn't have any desire to explore the map, the game did a good job of taking you everywhere you needed to go. I've heard there are secrets and easter eggs in the game but I never really wanted to go and find any.
Hopefully Campo Santo will make another game like Firewatch in the future, maybe even a sequel. There's no reason both the main characters could do the fire watch again next year, after parting to live their lives for several months. I really enjoyed it so with a few improvements I think I may even love a successor.