Green Room (2015)

Green Room is a claustrophobic survival thriller about a punk band trapped in a remote venue by a group of neo-Nazis. The film is raw, violent, and incredibly stressful, focusing on the desperate, improvised tactics the band uses to survive. It is a grounded, realistic take on a siege scenario that avoids typical horror tropes. The intensity comes from the feeling of genuine danger and the brutal, sudden nature of the violence.

It is a highly effective, albeit very dark, thriller that keeps the audience on edge from start to finish.