Great idea, this is typically how people review films and albums to their friends - a short sentence. It will be interesting to see how it develops with more content.

The short sentence format sounds compatible with some sort of Twitter interaction. Have you considered allowing users to tweet their review and use a hash tag to reference your site and the film in question? Or have it the other way round - they can sign in with their Twitter account (or use OAuth) and their review gets tweeted. Those are just quick ideas - there must be something that can be done in this space.