The acting was brilliant. Bjork's role was major, and her acting would pretty much make or break the film, and she plays Selma with an enchanting combination of naivety and childlike wonder, allowing audience sympathy throughout the story. Siobhan Fallon as the prison guard was also amazing.
Zeljko Ivanek had a small role as the DA... and he's in OZ so I had a bit of a OZ flashback, particularly with the Shirley Bellinger story-arc (females on death row etc similarities etc.)
The camera... oh the camera. Lars von Trier does not like tripods it would seem. The camera movement wa extreme. Moving this way and that, swinging between two people in a conversation, zooming and then refocusing (or could it possibly be auto-focus? Say it isn't so!). Oh and there were jump cuts. Mid conversation jump cuts. This filming style gave the film a documentary-like feel. The exception to this was the song/dance numbers, which used stationary cameras and richer colours, creating a contrast from the real world.
All in all, a very powerful film (the last scene was crazy-intense), I'm not sure if I particularly liked it or not; I'm not sure if it's even possible to like or dislike it... it just is.