If you loved Case Closed: The Crimson Love Letter, try Detective Conan: Dimensional Sniper
A bridge between a film you've already seen and one most people haven't. Here's what they share, and what the second one does that the first one doesn't.
You already loved

Case Closed: The Crimson Love Letter
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Detective Conan: Dimensional Sniper
What they share
Both films are directed by Kobun Shizuno, and they sit in Action / Animation / Mystery territory. If that's the register that drew you to Case Closed: The Crimson Love Letter, the second film will land in a comparable space — through a different lens.
What Detective Conan: Dimensional Sniper is
Tokyo. Winter. A shattered pane of glass. High-rise buildings become shooting galleries as a phantom sniper picks off random civilians, one by one. Conan follows the rifle's trail into a maze of military secrets. A deadly serious entry in the anime procedural franchise.