Pretty good, but with a common flaw.
The sisters wrote and directed a very intricate, very clever, very entertaining movie, a dark comedy of sorts. I enjoyed it, but it has one glaring flaw that unfortunately is too common in certain movies.
Recall how the last couple of scenes took pains to explain to the viewer what all happened? A really good movie doesan't have to do that, the scenes and dialog leading up to the end are put together so well that the viewer understands it all WITHOUT the need to explain it.
Take "Fargo" for example, a movie that looks and feels a lot like "Thin Ice." When it ends we know everything with no need for it to be explained to us. Or another of my favorites, "Pleasantville". Yes, the occasional unattentive viewer will ask "What exactly happened there?" but for the most part really good, well-crafted movies do NOT need an explanation at the end.
The fact that this one does simply means the sisters were not clever enough to pull together the whole story without the explanation at the end.
TxMike
Make a choice, to take a chance, to make a difference.