I love the sense of humor of not explaining anything about Doug and having him be in character the whole time. It reminds me of a play I once saw where the main character was a dog (played by a human of course) and she really nailed the role (as does Doug.)
I was confused by the effect of alienation. It would make more sense to me that having Chuck see Doug as helpful/vigilant/friendly would be a good way to make him less worried about what Doug gets up to and alienating would make Chuck more eager to lock Doug outside or get rid of him. I do think the alienation arc is humorous and should be kept as an option.
I also feel like having someone appear during a scene when they weren't in the house doesn't feel right unless they have to arrive for a scene to make sense.
I see some negative comments about the voices, but I thought they really added to the experience.