Trying to move from subtitles to native content—why is the spoken Croatian so much faster than the textbook?

I’m at an intermediate plateau and I’ve started watching Croatian films without English subtitles. The problem is I catch maybe 30% of the dialogue because of the way they run words together and drop syllables. Is there a specific listening method to train my ear for these natural 'rushed' speech patterns, or should I just keep grinding through the content and hope it clicks?