Nor did I find it depressing - after the anguish & pain suffered previously, the joy of the last 10 minutes or so was expressed beautifully by the actors, from a wonderful script.
I didn't think I would like it at first, but gave it another go and was hooked. It was a very complex finish, though. If I understood it right, it was desperately sad. I liked the way River's partner looked out for him and helped him.