The toons spit out real water.
The toons reflect real moving light.
The toons smoke real cigars.
The toons tote real guns.
The toons smash real plates.
The toons look real people in their real eyes.
These toons aren't just drawn on top of an empty space in an already recorded scene. They are interacting with and living in the real world.
Completely, utterly groundbreaking. 100%, without a doubt, one of the most technically proficient films ever made. Pushes the boundaries of movie magic. Still jaw-droppingly impressive over 30 years later. This film is just pure craft and talent. Some of the best filmmaking I've ever seen.
It also manages to be a fun noir with loveable characters, a love letter to cartoons, and family-friendly (even though Judge Doom scared the shit out of me as a kid) while keeping the adults entertained. I love it.