It’s his best yet.  Terrible movies come out all the time and people like them.  Mediocre ones get lots of Oscar attention, even when few people outside of the Academy have seen them.  Interstellar reminds us that truly great films can and do get made.  You can click on the IMDB link to get a description of the plot and learn who the cast is, but really, if you have the time, just see it.  I’ll describe some of the more general aspects of the film, and then afterward discuss plot elements that give the story away.

• Matthew McConaughey: He did extraordinary work in this film.  Across the board the acting was great to middling, but in McConaughey’s case, he simply was Cooper.  At no point in the film did you get the feeling that this was a man playing a role.  You simply witnessed the remarkable experiences of a brave man doing the best he could in unbelievably difficult circumstances.  How often do you see that in a film?  Especially a genre film?
• Family Life: It’s easy to go high-concept and get the audience’s waterworks going when it comes to family themes in a movie.  As sophisticated moviegoers, we’ve seen it all before.  This was different.  There was a level of complexity and anguish brought to this story that’s rarely seen in science fiction; the concept of time-debt was used here very well and was reminiscent of Dan Simmons’ classic Hyperion novels.  It added tension to an already taut story.
• Immersion: There is simply no illusion a talented special effects crew can’t create with current technology.  While the effects weren’t necessary for the plot, everything looked as though it belonged: spacecraft gliding through space, the lander on the water planet, the camp on the ice world.  It was all just there.  No imagining necessary.  It looked perfectly real.  Even the robots were awesome; a lot of work was put into them to make them characters but not mascots.  
• Our Future: Near the beginning of the film was a moment that showed you very clearly that this was not only set in the future, but that the future is a bleak, even terrible place.  You’ll know it when you see it; it’s jaw-droppingly ugly.  The Earth’s peril is both existential and philosophical, which makes McConaughey’s journey that much more important.

I don’t want to talk in hints, but if you haven’t seen this film, I would hate to spoil it for you.  Just watch it like I did, with wide eyes.  Five out of five stars.

• Matt Damon: Unfortunately for him, Matt Damon’s become such a star that he’s no longer a believable character any more, no matter who he plays (unless it’s Jason Bourne).  He did a good job, but he’s a little miscast, because he took me out of the film a little.  I knew he was squirrelly from the beginning: he talked way too much.  Also, anyone who tells you to NOT check or double-check something is a bad guy.  He had some of the best lines in the film, with his alternately pathetic apologizing and disturbing questions of the man he was trying to murder.
• Bootstrapping: There’s a massive plot hole that the whole film is based on, and I can’t seem to get my head around it.  Everything that happens, from the wormhole appearing to Cooper saving himself via the tesseract is based on a recursive time loop.  If the future humans were the ones who sent the wormhole back in time to save us from a doomed Earth, how did those future humans survive to do it?  There should have been no future humans alive to save us.  The only way to explain it is to go into fifth-dimensional physics and play around with multiple universes, but if that’s the case, then why bother?  There’s an infinity of doomed Earth you’d have to save.
• If B then A: It’s possible that the future humans sent the wormhole back in time not to save themselves, but to save Plan A humans.  The future humans could simply be the descendants of Plan B, who were going to survive anyway because Anne Hathaway unfroze their embryos on the new planet she’d found.  So what they did was save Earth’s population by sending the wormhole and tesseract back in time for Cooper to fly through and find.  
• Me, Me, Me: I almost never geek out about movies, but I just dug this one.  Probably because I saw it with my brother; it was the first time we’d seen a movie in the theater together in over a decade.  He read the novelization and told me it was just a scene-by-scene novelization of the movie; no great revelations there.