Aside from being hokey/sappy/corny, Interstellar is just a really long movie that plays long. Gone Girl was about 140 minutes, iirc, but the time flew by and I would have liked it to go on a bit more.
And what is the big deal with Jessica Chastain? She was OK, but I don't think she did anything any other actress couldn't (thought the Twilight girl was much better, believe it or not). It's a mystery why some actors become the hot property of the year.