With its voice-over, body doubles, and callbacks, the ending of Kiss Kiss Bang Bang can be confusing on first watch. Kiss Kiss Bang Bang is a neo-noir comedy directed and written by Shane Black. The film follows and is narrated in voice-over by, Harry Lockhart (Robert Downey Jr.), a small-time burglar who lands in the LA movie scene when an admission of guilt is mistaken for method acting. In LA, during Christmas, when so many Black movies are set, Harry gets tangled up with private eye "Gay Perry" van Shrike (Val Kilmer), and together the odd couple solves a murder mystery.
https://screenrant.com/kiss-kiss-bang-bang-ending-explained/