Even native speakers do not understand every single word that is spoken on tv. Sometimes we just figure out what they said from context and sometimes we don't have any idea what they said. The actors sometimes do not enunciate their words very clearly. If you understand almost all of what is said, this is probably as good as you can expect. Also, it could be that it is difficult to guess what they said because they are using current slang or an idiom. I don't know if this helps, but I think sometimes English language learners think that a native speaker would understand 100%.