The new Heaven's Feel film trilogy adapts the Heaven's Feel route of the original light novel, which features Sakura Matou as the main love interest. The Heaven's Feel route is notable among the others from the game due to its much darker content and expansion on the lore of the series, so fans were excited to see the new films either way. Director for the Heaven's Feel film trilogy Tomonori Sudou has mentioned that he felt that Shirou and Sakura's relationship was the most important part of the Heaven's Feel route, so it seems that he's adapted the erotic content from the original game as a form of this. This is especially notable as the two previous TV anime adaptations of the visual novel focused on the Fate route in which Shirou ended up with Saber and the Unlimited Blade Works route where Shirou ends up with Rin Tohsaka did not include any of the original game's erotic content. The third route has a stark contrast to the other two, and now the film trilogy for it will have a stark contrast from the other anime releases that have come before. Shirou feels like a much different main character in this arc than the others, and the inclusion of a sex scene will help illustrate such a major shift from the other iterations of the character seen before.
Don't you remember anything about being gentle, you beast!? Tohsaka still scolds me. And it's not in her usual arrogant way. She's yelling at me in a way that makes me realize I've done a bad thing. I told you it hurts.
Often, players will come to a "decision point" where they are given the chance to choose from options displayed on the screen, typically two to three at a time. The time between these decision points is variable and during these times, gameplay pauses until a choice is made that furthers the plot in a specific direction. There are three main plot lines that the player will have the chance to experience, one for each of the heroines in the story. To view all three plot lines, the player will have to replay the game multiple times and choose different choices during the decision points to progress the plot in an alternate direction. When interacting with the heroines with the routes, an "affection meter" is created which is raised by giving them an answer that pleases them.