Warning: It's not an Horror movie. It's an Action movie

I'm a horror fan... I literally live for horror... I have horror themed tattoos on my body...

Don't Breathe most certainly IS horror. It started off as a suspense thriller, but as twists unfolded and more things were at stake, it quickly changed pace and became a full fledged horror flick.

Warning- it's also not a good movie

Most would agree that it is a scary film, if not just for the macabre, abrupt occurances of violence.
It is perhaps a horror movie for the same reason. I agree that the term is misleading since it is usually applied to illogical movies involving fantasy. Too often it is misapplied to good, solid, science fiction (Alien, etc,).

Great movie. Loved it. But IMO, it's suspense/thriller. After months of reading all the praise as a horror movie, I was like "whaaat?"

Yes because getting stalked by a deranged killer in a creepy house isn't horrific @ all. Good call lol.

Who would have thought that horror is divided into this many subgenres. LOL

Subgenres

Horror films can be divided into the following subgenres, a single film may overlap into several subgenres:

-Action horror – A subgenre combining the intrusion of an evil force, event, or personage of horror movies with the gun fights and frenetic chases of the action genre. Themes or elements often prevalent in typical action-horror films include gore, demons, vicious animals, vampires and, most commonly, zombies. This category also fuses the fantasy genre. Examples include: Aliens, Predator, Hansel & Gretel: Witch Hunters, I Saw the Devil, Priest, and Feast.
-Comedy horror – Combines the elements of comedy and horror fiction. The comedy horror genre almost always inevitably crosses over with the black comedy genre. The short story The Legend of Sleepy Hollow by Washington Irving is cited as "the first great comedy-horror story".[36] Examples of comedy horror films include: Jennifer's Body, Teeth, Nina Forever, Slither, Army of Darkness, Zombieland, and Idle Hands.
-Body horror – In which the horror is principally derived from the graphic destruction or degeneration of the body. Other types of body horror include unnatural movements, or the anatomically incorrect placement of limbs to create 'monsters' out of human body parts. David Cronenberg is one of the notable directors of the genre. Body horror films include: Starry Eyes, Videodrome, Dead Ringers, Contracted, The Thing, The Fly, and American Mary.
-Holiday horror – Involves a psychopathic killer stalking a sequence of victims in a violent manner during Christmas. The murders are often committed by someone dressed as Santa Claus, a snowman, an elf, or other Christmas character. Examples include: Silent Night, Deadly Night, Jack Frost, The Gingerdead Man, Black Christmas, Krampus, and All Through The House.
-Horror drama – A film that focuses on imperiled characters dealing with realistic emotional struggles, often involving dysfunctional family relations, in a horror setting. The film's horror elements often serve as a backdrop to an unraveling dramatic plot. Examples include: Dark Water, Lights Out, The Babadook, Let the Right One In, Antichrist, Excision, Thirteen Ghosts, Mirrors, and Audition.
-Psychological horror – Relies on characters' fears, guilt, beliefs, eerie sound effects, relevant music, emotional instability and at times, the supernatural and ghosts, to build tension, scare and further the plot. Notable psychological horror films include: Repulsion, Rosemary's Baby, The Shining, May, I Know Who Killed Me, The Changeling, and The Uninvited.
-Science fiction horror – Often revolves around subjects that include but are not limited to killer aliens, mad scientists, and/or experiments gone wrong. Examples include: Frankenstein, Species, Mimic, Alien, The Thing, The Blob, Apollo 18, The Faculty, and Resident Evil.
-Slasher film – Often revolves around a serial killer who systematically murders people through violent means. Examples include: Psycho, The Texas Chain Saw Massacre, Halloween, Friday the 13th, Black Christmas, A Nightmare on Elm Street, You're Next, and Scream.
-Splatter film – These films deliberately focus on graphic portrayals of gore and graphic violence. Through the use of special effects and excessive blood and guts, they tend to display an overt interest in the vulnerability of the human body and the theatricality of its mutilation. Examples of splatter horror films include: Inside, Train, The Human Centipede, Hostel, Saw, Blood Feast, Storm Warning, and Maniac.
-Supernatural horror – Includes menacing ghosts, demons, or other depictions of supernatural occurrences. Often, supernatural horror films combine elements of religion into the plot. Common themes include vengeful ghosts, witches, the devil, and demonic possession. Examples include: The Ring, The Grudge, The Amityville Horror, The Omen, The Exorcist, Paranormal Activity, The Blair Witch Project, and When the Lights Went Out
-Gothic horror – Gothic horror is a type of story that contains elements of goth and horror. At times it may have romance that unfolds in the setting of a horror tale, usually suspenseful. Some of the earliest horror movies were of this subgenre. Examples include: Dracula, Sleepy Hollow, The Others, The Phantom of the Opera, Kill, Baby, Kill, Nosferatu, and Crimson Peak.
-Natural horror – A subgenre of horror films "featuring nature running amok in the form of mutated beasts, carnivorous insects, and normally harmless animals or plants turned into cold-blooded killers."[37] This genre may sometimes overlap with the science fiction and action and adventure genres. Examples include: Piranha 3D, Bats, Lake Placid, Rogue, Alligator, Eaten Alive, Eight Legged Freaks, and Jaws.
-Zombie film – Zombie films feature creatures who are usually portrayed as either reanimated corpses or mindless human beings. Distinct subgenres have evolved, such as the zombie comedy or the zombie apocalypse. Examples include: Dawn of the Dead, REC, 28 Days Later, Deadgirl, Dead Snow, Night of the Creeps, and Messiah of Evil.