This Hong Kong crime horror. This one. Where the beginning is brutal then it becomes a cop procedural with comedy characters with occasional cuts to the killer murdering a staff member of his restaurant because they looked at him funny then back to the comedy. With the occasional cannibalism.
Tonal shift doesn't begin to cover the complete holy fuck of the last 20 minutes. Just be prepared. You'll be wondering why all the good stuff happened so early then...uh...blam.