How exactly did "solving gravity" allow them to launch NASA and save all human life? Did they develop some kind of anti-gravity? Isn't that theoretically impossible, no matter how much information of an unspecified nature one gathers from inside black holes? If people in the future are capable of building a device that can send messages through time via gravity, why didn't they just send those messages themselves, instead of waiting for someone from the past to stumble upon the device and use it? Come to that, why set this device to focus on the bedroom of a little girl who might be able to take the information to NASA, and not just focus it on NASA? How come Coop looked about 50 when, according to the film, he was no older than 35 when he left Earth?
The beginning was awesome, then the whole space section deliberately makes no sense so that the end can explain it all which may have been just about bearable if the space section wasn't over 2 hours long and wasn't riddled with plot-holes in its science and even the concepts it makes up, and didn't bash you over the head constantly with forced symbolism and metaphors and themes (if I hear 'Do not go gentle' one more time I will attack something). “Interstellar” starts out as season 1 of "Space: 1999" with lots of big ideas and metaphysical concepts, but ends like season two, in fact I was expecting Fred Freiberger to credited as an executive producer. Or more bluntly, this started out "Wrath of Khan" and ends like "The Final Frontier". The end did solve most of the issues the film had plot-wise, but not pace-wise; by the time it gets to the end it's already lost you and you'll probably laugh at how comically idiotic it is. It doesn't help that apart from the father-daughter duo that certainly had its moments, none of the characters have any real depth or are developed and the dialogue is so inane and boring I challenge anyone to quote to me one line that wasn't a trailer line in the entire script. I checked my watch three times during it and jumped out of my chair the second it cut to black. As for the effects, when it does go full 70mm IMAX cinematography it is one of the most stunning-looking films ever made, but in honesty the worlds are pretty bland and there isn't nearly enough time spent on them. If you stitched all the scenes the film hangs its hat on spectacle-wise together you'd probably get about 10-20 minutes max of screen-time. I watched this again when it came to Netflix to get an opinion on it. It's clearly Nolan got way too carried away with himself and it’s a shame because if this was a 1.5 hour simple space-exploration movie with some intrigue and tight dialogue and a lot more IMAX scenes it probably would have been amazing.
I wonder if there's a conflict between Nolan's desire to make emotional films about love and loss, and his love of intricate clockwork plots. Maybe emotional impact needs looser plotting, and clever puzzle plots need a cooler approach. Perhaps you have to choose between making the audience feel and making them think. For me that conflict is why it fell apart in the last reel*.
(*) yes, it was a reel, and seeing that old 35mm flicker which I've spent far too much of my life looking at in the dark did add a lot of emotional impact for me, especially as I'm fairly confident that cinemas won't exist in ten years' time.
Bottom-line: It was filled with plot holes and inconsistent science (even more so than the "The Dark Knight Rises"). Imagine McConaughey in the movie; upon finding himself inside a pocket universe of infinite bookcases, I burst into a very audible laugh and found myself unable to stop for a good few minutes (when I watched this in a movie theatre I thought someone would come and kick me out). Conceptually, I had very high hopes for this film but found completely let down with the last 15 minutes. I wouldn't say that this is a good film but I would say it it's worth watching, even if it's just for the coldly maniacal Matt Damon and the bizarre and strangely funny robots (Did you see that little alcove in the 5-dimensional bookcase? The one with some clueless monkey laughing in a darkened pit? It was me...)
NB1: a friend of mine says “Signs” is much better than this one. Nope. “Signs” is most definitely not superior to “Interstellar”! “Signs” is a god-awful farce. The first part of it has some well-crafted tension and at least one genuine shock, but then “Shyamalamalamadingdong” farts it all away with an ending so titanically stupid it makes you wonder if he got one of his children to write the script for him. Aliens are so allergic to water it burns them like acid - and they don't wear clothes! Convenient for the humans, and somewhat daft of the aliens to visit a planet with a surface that is 70% water. Why are they naked as well? Are we supposed to believe they can travel across the stars but haven't figured out how to create a raincoat? Nothing about the ending works at all and renders the rest of film a complete nonsense.