A small and rather specific subgenre is the one-set hostage thriller - usually very few cast members (mainly just the hostage and captor) and usually one set (there may be additional locations for some scenes, but most of the film takes place in one area). When done well, they make for compelling cinema, with the two actors doing heavy lifting to carry a film and maintain dynamic personalities.

What are your favorites that might fit the criteria? I'm looking for more suggestions. I've already seen Hard Candy, and Death and the Maiden and The Disappearance of Alice Creed are on my list.

I can think of four offhand, but all had multiple hostages and captors:

THE PETRIFIED FOREST (1936) A robbery gang takes over a roadside diner and holds the customers and staff hostage. Bogart leads the gang; Leslie Howard is a customer and Bette Davis is a waitress.

SUDDENLY (1954) Frank Sinatra is leader of a team of assassins who take over an apartment so they can shoot the visiting President (Eisenhower) when he arrives in town.

THE DESPERATE HOURS (1955) - based on a play about two escaped cons who take a family hostage in their home. Paul Newman played the main con in the play, Humphrey Bogart played him in the film.

ROCK ALL NIGHT (1957) Roger Corman cheapie in which two criminals hold a bar full of patrons hostage after the Platters have performed a couple of songs (for marquee value) and then left. All shot on one set.

Great Hammer film:

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Does Panic Room qualify?

Phone Booth
Funny Games

Closet Land

Tape? It's not really a hostage situation but it does involve some blackmail.

One of the better unknown movies from the past few years, "The Exam" is in this genre. Mostly a British cast, which is why it's not too famous here.

Reservoir Dogs, perhaps.

In that same vein, Deathtrap with Michael Caine and Christopher Reeve.

I think How to Rob a Bank counts although I never saw the whole thing.

It's grindhouse remake:

Yea I have seen that one and it was pretty good.

I watched that one when I first got Netflix.