Lots of ways to use silent videos in the classroom, see some ideas in this post.
Here are 4 possible ways you can do a lesson with this video.
1. Backdoor. A few students have their back to the screen. Other students describe the action, what's happening. Can they keep up? Switch roles part way through. Lastly watch again as the teacher narrates for the class who have their head down!
2. Prediction. Play the video and stop often asking students what they think will happen next. At the end of the video, get students to write a sequel/continuation for the story called "Oktopodi 2: What's Next"
3. Caption writing. Use the ppt attached and provide to students. They write captions for the film and then play the film in class and have the students read/narrate. Lots of fun!
4. Retelling. Students use the cards attached after watching the film. Cut them up and students reorder and retell the story to the rest of the class. You'll have numerous versions!
With all of these lessons - you can preteach and prompt student background knowledge with this neat Prezi presentation.