A man walks into a bar... sits down at the bar and tells the bartender, let me tell you a story: "A man walks into a bar..."
For a film about the nature of storytelling, it has very little story to tell. It eventually gets to the point, but not before you've had to endure numerous dull nested flashbacks and stories within stories that all lack substance. For the longest time, only the noir-ish lighting and ominous music really mark it out as a horror film at all.
It doesn't surprise me it was based on stage play and perhaps it works better on the stage though if it's a verbatim transcription, I find that hard to believe as the dialogue is just so pedestrian. The post credit sequence after the 'sting', or re-contextualization of the opening image, is just a bunch of leftover drone footage. Pointless and tedious machismo.