Film review: Coherence (2013)

This is a fun little film (free if you have Amazon Prime) that manages to be an entirely special-effects-free science fiction film set entirely around a dinner party for a group of pretty obnoxious Angelinos (at least, I think it's in Los Angeles - could conceivably be the Bay Area given that one of them is supposed to run Skype, but (a) that's based in Estonia, and (b) their house is nice, but not that nice).  I only recognized one of the actors, who is playing an actual actor who claims to be in Roswell.  But I've never seen that show, and it turns out what he was actually on was Buffy the Vampire Slayer (which I've also never seen, but it so permeated the zeitgeist for a while there that I suppose I must have picked it up by osmosis).  It reminded me a little of The Exterminating Angel, if only because of the whole dinner party aspect, but I don't think it had any socially redeeming commentary in it.  The essence of the idea is this: a comet is passing over and one of the party's number's brother, who is some bigshot science professor at one of the California schools, has told him to call him if anything strange happens.  Another party-goer, a dancer named "Em" recounts a story of when it last passed over and a woman in Finland insisted that the man in her house was not her husband.  The police came and said "we know that's your husband - why do you say it isn't?" "Because last night I killed my husband." Dah dah DAHHH!  Adding to the paranoia is that cell phone service and (gasp!) the internet go out, and not only that, but two people's phones actually shatter as they're using them.  Then the power goes out - everywhere in the neighborhood except for one house a couple of blocks away.  The guy with the egghead brother decides to go over there and see if they have a landline so he can call the brother, and another guy agrees to go along.  While they're gone, there's a bang on the door, but nobody's there, and people start to get really rattled.  However, they remember that they have a generator (seems like something you wouldn't forget...) which they turn on and now they have power again.  Then the pair return (or do they?) carrying a metal box that they "stole" from outside the other house, and the guy with the brother has a cut on his head and is very reluctant to say what he saw when he looked in the window of the other house.  But finally he admits he saw... them.  That is, the people at the party.  And here you have the plot: it's a "Spiderverse"/"sliding doors" alternative realities movie, only the comet is causing them to be accessible to each other.  Oh, and they open the box, and besides a ping pong paddle, it contains pictures of every one of them with numbers on the back.  Things get hairier and hairier, with more and more alternate realities, and the actor falls off the wagon, and the dancer's boyfriend's ex-girlfriend hits on him... and, well, you'll just have to see it.  If I had to summarize the real upshot of the film, it's just a really torturous way for Em to learn to commit to things.  (And in the course of doing so she attempts a murder-suicide.)  Is it good?  Well, yes - surprisingly so.  The performances are natural (almost to a fault - there's a lot of shakycam and people talking over each other) and the ideas ingenious, although there a plot holes galore if you think too hard about it (there shouldn't be two rings!).  But that's part of the fun!