This is basically a Columbo episode, we see the murder and the coverup and then we slowly watch the tension build as our detective picks up the clues and the killers get more and more unhinged, so of course I'm in.
Looks great cinematically of course, even without the single-take illusion the staging is fantastic. It's not just a gimmick or an experiment, the fact that we never leave the apartment and never cut away between scenes makes us feel like we're right there which really works for the tension.
This Hitchcock kid, he's got a career in front of him if he keeps this up. But seriously, I've far from seen all of them, but I this is my favourite of his. It's really a masterpiece, a must watch, and great fun too.
Also, of course they are gay. Undeniably, incredibly, chronically gay.