Never a dull moment in this one as a couple of dodgy detectives investigated and interrogated a brutal surgically precise murder. Overall I guess you could have called the tone manic bad taste, which is good enough for me in terms of being black comedy. Cynicism, sarcasm, and cancer jokes, nothing was taboo and the film benefited from it. The epilogue was a bit unnecessary, and cinematography definitely the weak part of the film as lighting was lacking. However for parodying David Caruso/CSI you have my respect.
Have to say I was a little confused with the genre setting in your film. I was getting crime/thriller vibes with plenty of great cynicism but even still not a lot of the 'hit&run' kind of black comedy tropes we all know and love as New Zealanders. Although saying that, it was funny and dark and awkward so... why try and always adhere to filmic conventions shhm. Good job.