I never got this whole trial. There ws penty of evidence showing that Guede was int he room, and he even admitted to being at the murder scene.
http://www.theguardian.com/world/2009/dec/22/rudy-guede-sentence-kercher-murder
Police tracked Guede to Germany after finding his handprint in Kerchers blood. After his arrest, Guede claimed he was at the murder scene but in the bathroom when a man entered the house and killed Kercher.
There was pretty much overwhelming evidence that he was there, and he had committed crimes before, and his fingerprints were found in blood. He claimed to be in the bathroom while someone else came in the room and murdered Meredith. Yet he never thought to call an ambulance - he instead went to a friends house and then a night club. Doesn't make sense if he was not the murderer.
I don't get why Amanda acted strangely, and never got her story straight in the beginning, but the guilty verdict is really a stretch.