The trailer pretty much lets the film speak for itself -- troubled girl in crappy circumstances, struggling to stay afloat. But like Red Road, which took a simple premise and formed it into a gut-wrenching affair, Fish Tank looks to have a whole lot of depth to back up the usual coming-of-age tropes.
As for the killer reviews... It's got a 92% fresh rating out of 36 reviews, and our Todd Gilchrist wrote from AFI: "Arnold has really created one of the absolute best coming-of-age stories I've seen in several years, because it accurately observes that sometimes just being able to survive is triumph enough, even if all of your hopes and dreams don't come true." (Part of that quote appears in the film's trailer.) On top of that, it's won almost every award it's been nominated for.
Need any more reason? Head over to Apple to see for yourself.