Earlier quoted context omitted.
One of the only movies that remains intriguing throughout despite being basically a single conversation.
I happen to love certain niche movie genres, which happens to include "dinner party movies". Feel free to list some recommendations, if you like "people talk in a room" movies. Some of my favories: Coherence (scifi) Garden Party (sleazy young adult Los Angeles drama) Murder Party (low budget horror comedy) How English sounds to non-English speakers (youtube) Circle 2015 (scifi)
There's some play adaptations which have few characters and mostly dialogue: Carnage, Who's Afraid of Virginia Woolf, Glengarry Glen Ross
Linklater's "Before" trilogy is also heavily dialogue-based, but the there are multiple locations.