Still in interested? I saw it yesterday and this is how it ends:
After telling her he had killed her father Kurt wants sex with Lisa. Lying under his threat Lisa remembers her father raping her when she was a child. She frees herself from Kurt and shoots him in the leg. In the following fight Lisa falls her head hitting the ground. Kurt leaves her unconsious, puts fire to the hunting hut and flees with a boat on the lake. Lisa wakes up and Kurt sees her standing at the lake's shore. When Kurt aimes to shoot Lisa the pile that stook her father to the lake's ground comes up through the boat's bottom. Kurt drowns. Martin appeares to take Lisa in his arms. They kiss. 'Lets go home', Lisa sais and so they do. She leaves her father's leather coat in the forest near the burning hut.