Pretty intense movie. Might provoke some lines of thought you harboured about appropriate behaviour.
If you're German, watch the translation. It's infinitely better. "NORMAAAAALEEEEEES BIIIIIIIIIIIIIILD!"
If you think Inception had a complicated plot, this movie isn't for you. Really. There's charts with loops on the Internet which show the plot and what's happening when. You'll probably need to watch this movie at least twice.
It's very, very good.
A grossly understated movie. The actors do a really incredible job, and the topics of their more or less ninety minutes long conversation are very, very thought provoking. You really need to watch this if you enjoy intellectual debate.