Alright, nearly 24 hours out from my last post and no one else had ventured a guess so I'll do the reveal:
It's Vincent D'Onofrio's directorial debut (feature length, at least)
Don't Go in the Woods.
It was shot on a budget of ~$100K, featuring "actors" (in the loosest sense of the word) cast from a coffee shop near the director's home, filmed over 12 days mostly in the woods owned by D'Onofrio and has what I can only assume is a "You owe me one" cameo by Eric Bogosian (the man with the white cap in the third image I posted).
I really can't convey accurately how bizarre and awful it is - it's a slasher film but it's also a musical.
The musical aspect of it just saturates the entire film and any horrifying moments almost feel like surreal comedy as a result (if you're feeling adventurous, someone (and rest assured it was not me) has uploaded a number of clips and even entire parts of the film onto YouTube - none of which seem to have been hit by DMCA notices because I have to seriously wonder if anyone involved with the film cares enough to even bother).
Anyway, that's that. The opportunity to post the next one is open to anyone willing to do so.