If you loved Detective Conan: Episode One - The Great Detective Turned Small, try Detective Conan: The Raven Chaser
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.

Detective Conan: Episode One - The Great Detective Turned Small

Detective Conan: The Raven Chaser
What they share
Both films are directed by Yasuichiro Yamamoto, and they both carry the foreign gem mood tag, and they sit in Animation / Crime / Mystery territory. If that's the register that drew you to Detective Conan: Episode One - The Great Detective Turned Small, the second film will land in a comparable space — through a different lens.
What Detective Conan: The Raven Chaser is
Nagano Prefecture. A crow's feather. Six murders across Japan connect in a disturbing pattern. Conan Edogawa realizes a Black Organization spy is embedded with local police. Gin's assassins close in. See it for the puzzle-box plotting, stay for the sheer anime audacity.