“Within” means literally “inside of,” but when you want to compare similarities or differences between things you may need “among” instead. It’s not “There are some entertaining movies within the current releases,” but “among the current releases.” But you can use “within” by rewriting the sentence to lump the movies together into a single entity: “There are some entertaining movies within the current batch of releases.” A batch is a single thing, and the individual films that make it up are within it.