I don't think even Einstein would've understood this movie in one sitting. The trailer doesn't spoil anything and the movie IS thought-provoking. Nothing is dumbed down! If you haven't seen Primer yet I'd suggest you watch it. If you've already seen it, I'd say watch it again... and again. It's worth it in the end. If you're impatient, wikipedia will be your friend, especially the external links. Don't deprive yourself of any riches, watch something that challenges you for once.