Peter Falk is so great as a classic hardboiled detective type
If you don't get enough of it in Murder by Death, this flick will definitely set you up. I think what makes it work so well is that Falk could have played the type straight had he wanted to, in the same way Spaceballs works because Bill Pullman could have played a genuine space hero in a straight-up sci fi flick. It's not impossible to imagine say Chinatown starring Falk rather than Nicholson. Let me qualify that by saying Nicholson is great.
I love Columbo, but he's distinctly seventies, whereas Sam and Lou are very 30's/40's noirish.
Reason is a pursuit, not a conclusion.